diff --git a/lib/jam_ruby/models/band_invitation.rb b/lib/jam_ruby/models/band_invitation.rb
index 720f532cb..94a830fd3 100644
--- a/lib/jam_ruby/models/band_invitation.rb
+++ b/lib/jam_ruby/models/band_invitation.rb
@@ -11,35 +11,22 @@ module JamRuby
 
     def self.save(id, band_id, user_id, creator_id, accepted)
 
-      # ensure recipient is a Musician
-      user = User.find(user_id)
-      unless user.musician?
-        raise JamRuby::JamArgumentError, "A Band invitation can only be sent to a Musician."
-      end
-
+      # ensure certain fields are only updated on creation
       if id.nil?
+        # ensure recipient is a Musician
+        user = User.find(user_id)
+        unless user.musician?
+          raise JamRuby::JamArgumentError, "A Band invitation can only be sent to a Musician."
+        end
+
         band_invitation = BandInvitation.new()
+        band_invitation.band_id = band_id
+        band_invitation.user_id = user_id
+        band_invitation.creator_id = creator_id
+
+      # only the accepted flag can be updated after initial creation
       else
         band_invitation = BandInvitation.find(id)
-      end
-
-      # band ID
-      unless band_id.nil?
-        band_invitation.band_id = band_id
-      end
-
-      # user ID
-      unless user_id.nil?
-        band_invitation.user_id = user_id
-      end
-
-      # creator ID
-      unless creator_id.nil?
-        band_invitation.creator_id = creator_id
-      end
-
-      # accepted flag
-      unless accepted.nil?
         band_invitation.accepted = accepted
       end
 
@@ -49,7 +36,7 @@ module JamRuby
       # TODO: wrap this and previous block in transaction
       # accepting an invitation adds the musician to the band
       if accepted
-        BandMusician.create(:band_id => band_id, :user_id => user_id, :admin => false)
+        BandMusician.create(:band_id => band_invitation.band.id, :user_id => band_invitation.receiver.id, :admin => false)
       end
 
       return band_invitation