diff --git a/app/controllers/checkiners_controller.rb b/app/controllers/checkiners_controller.rb
index 2258f3075..86f511677 100644
--- a/app/controllers/checkiners_controller.rb
+++ b/app/controllers/checkiners_controller.rb
@@ -3,12 +3,16 @@ class CheckinersController < ApplicationController
   before_action :validate_organizer!
 
   def index
-    @checkiner_rsvps = @event.attendee_rsvps.where(checkiner: true).includes(:user)
-    @potential_checkiners = @event.attendee_rsvps.where(checkiner: false).includes(:user)
+    render_index
   end
 
   def create
-    @rsvp  = @event.rsvps.find(params[:event_checkiner][:rsvp_id])
+    @rsvp  = @event.rsvps.find_by(id: params.fetch(:event_checkiner, {})[:rsvp_id])
+    unless @rsvp
+      @event.errors.add(:base, 'Please select a user!')
+      return render_index
+    end
+
     @rsvp.update_attribute(:checkiner, true)
     redirect_to event_checkiners_path(@event), notice: "#{@rsvp.user.full_name} is now a checkiner for #{@event.title}!"
   end
@@ -18,4 +22,12 @@ def destroy
     @rsvp.update_attribute(:checkiner, false)
     redirect_to event_checkiners_path(@event), notice: "#{@rsvp.user.full_name} is no longer a checkiner for #{@event.title}!"
   end
+
+  private
+
+  def render_index
+    @checkiner_rsvps = @event.attendee_rsvps.where(checkiner: true).includes(:user)
+    @potential_checkiners = @event.attendee_rsvps.where(checkiner: false).includes(:user)
+    render :index
+  end
 end
diff --git a/app/controllers/organizers_controller.rb b/app/controllers/organizers_controller.rb
index 74a7cca5d..5a69d0fca 100644
--- a/app/controllers/organizers_controller.rb
+++ b/app/controllers/organizers_controller.rb
@@ -4,7 +4,7 @@ class OrganizersController < ApplicationController
   before_action :validate_published!
 
   def index
-    @organizer_rsvps = @event.organizer_rsvps.includes(:user)
+    render_index
   end
 
   def potential
@@ -16,7 +16,12 @@ def potential
   end
 
   def create
-    @user = User.find(params[:event_organizer][:user_id])
+    @user = User.find_by(id: params.fetch(:event_organizer, {})[:user_id])
+    unless @user
+      @event.errors.add(:base, 'Please select a user!')
+      return render_index
+    end
+
     rsvp = @event.rsvps.where(user_id: @user.id).first_or_initialize
     rsvp.user = @user
     rsvp.role = Role::ORGANIZER
@@ -33,6 +38,11 @@ def destroy
 
   private
 
+  def render_index
+    @organizer_rsvps = @event.organizer_rsvps.includes(:user)
+    render :index
+  end
+
   def validate_published!
     @event ||= Event.find(params[:event_id])
     unless @event.published?
diff --git a/app/views/checkiners/index.html.erb b/app/views/checkiners/index.html.erb
index 49d2884c6..b12f6a626 100644
--- a/app/views/checkiners/index.html.erb
+++ b/app/views/checkiners/index.html.erb
@@ -3,6 +3,8 @@
 
 <%= render :partial => 'shared/organizer_breadcrumb', locals: {current_page_title: 'Checkiner Assignments'} %>
 
+<%= render 'shared/model_error_messages', model: @event %>
+
 <h3>Potential Checkiners</h3>
 <%= render 'shared/user_chooser',
            action: event_checkiners_path(@event),
diff --git a/app/views/organizers/index.html.erb b/app/views/organizers/index.html.erb
index 3651dae32..bb05d34f1 100644
--- a/app/views/organizers/index.html.erb
+++ b/app/views/organizers/index.html.erb
@@ -3,6 +3,8 @@
 
 <%= render :partial => 'shared/organizer_breadcrumb', locals: {current_page_title: 'Organizer Assignments'} %>
 
+<%= render 'shared/model_error_messages', model: @event %>
+
 <h3>Potential Organizers</h3>
 <%= render 'shared/user_chooser',
            action: event_organizers_path(@event),
diff --git a/app/views/shared/_user_chooser.html.erb b/app/views/shared/_user_chooser.html.erb
index 8d64eb82e..fc7066821 100644
--- a/app/views/shared/_user_chooser.html.erb
+++ b/app/views/shared/_user_chooser.html.erb
@@ -24,9 +24,13 @@
             }
           });
         <% end %>
-        $('#<%= select_id %>_<%= foreign_key %>').select2(options);
+        var $select = $('#<%= select_id %>_<%= foreign_key %>');
+        $select.select2(options);
+        $select.change(function () {
+          $select.closest('form').find('input[type=submit]').attr({disabled: !this.value});
+        });
       </script>
-      <%= submit_tag "Assign", class: "btn btn-primary", style: 'margin: 10px 0;' %>
+      <%= submit_tag "Assign", class: "btn btn-primary", style: 'margin: 10px 0;', disabled: true %>
     <% end %>
   </div>
 </div>
\ No newline at end of file
diff --git a/spec/controllers/checkiners_controller_spec.rb b/spec/controllers/checkiners_controller_spec.rb
new file mode 100644
index 000000000..a2e5f9602
--- /dev/null
+++ b/spec/controllers/checkiners_controller_spec.rb
@@ -0,0 +1,36 @@
+require 'rails_helper'
+
+describe CheckinersController do
+  before do
+    @event = create(:event)
+    @user = create(:user)
+  end
+
+  context "a user that is logged in and is an organizer for a published event" do
+    before do
+      @event.organizers << @user
+
+      sign_in @user
+    end
+
+    it "can see list of checkiners" do
+      get :index, event_id: @event.id
+      expect(response).to be_success
+    end
+
+    describe "assigning checkiners" do
+      it "can promote a user to checkiner" do
+        other_user_rsvp = create(:rsvp, event: @event)
+        expect {
+          post :create, event_id: @event.id, event_checkiner: {rsvp_id: other_user_rsvp.id}
+        }.to change { other_user_rsvp.reload.checkiner }
+        expect(response).to redirect_to(event_checkiners_path(@event))
+      end
+
+      it "shows an error if no user is provided" do
+        post :create, event_id: @event.id
+        expect(assigns(:event).errors[:base].length).to be >= 1
+      end
+    end
+  end
+end
diff --git a/spec/controllers/organizers_controller_spec.rb b/spec/controllers/organizers_controller_spec.rb
index 76407d38e..c19158cdf 100644
--- a/spec/controllers/organizers_controller_spec.rb
+++ b/spec/controllers/organizers_controller_spec.rb
@@ -68,7 +68,6 @@
   context "a user that is logged in and is an organizer for a published event" do
     before do
       @other_user = create(:user)
-      @event = create(:event)
       @event.organizers << @user
 
       sign_in @user
@@ -79,11 +78,20 @@
       expect(response).to be_success
     end
 
-    it "can create an organizer and redirect to the event organizer assignment page" do
-      expect {
-        post :create, event_id: @event.id, event_organizer: {event_id: @event.id, user_id: @other_user.id}
-      }.to change(Rsvp, :count).by(1)
-      expect(response).to redirect_to(event_organizers_path(@event))
+    describe "assigning organizers" do
+      it "can create an organizer and redirect to the event organizer assignment page" do
+        expect {
+          post :create, event_id: @event.id, event_organizer: {user_id: @other_user.id}
+        }.to change(Rsvp, :count).by(1)
+        expect(response).to redirect_to(event_organizers_path(@event))
+      end
+
+      it "shows an error if no user is provided" do
+        expect {
+          post :create, event_id: @event.id
+        }.not_to change(Rsvp, :count)
+        expect(assigns(:event).errors[:base].length).to be >= 1
+      end
     end
 
     it "can promote an existing volunteer to organizer" do