code: function( model, coll, options ) {
  			//console.debug('handleRemoval called; args=%o', arguments);
  			options = this.sanitizeOptions( options );
  			
  			_.each( this.getReverseRelations( model ), function( relation ) {
  					relation.removeRelated( this.instance, options );
  				}, this );
  			
  			var dit = this;
  			Backbone.Relational.eventQueue.add( function() {
  				!options.silentChange && dit.instance.trigger( 'remove:' + dit.key, model, dit.related, options );
  			});
  		}
docs: When a model is removed from a 'HasMany', trigger 'remove' on 'this.instance' and notify reverse relations.
  (should be 'HasOne', which should be nullified)