The best approach is to handle the OnClientTileClicking event for the TileList and determine whether it should be cancelled: http://www.telerik.com/help/aspnet-ajax/tilelist-client-side-events-onclienttileclicking.html.

A possible way to change the behavior is to pass the _cancel field value from the Clicking event of the Tile to the TileClicking event of the TileList with the following override.

			var $T = Telerik.Web.UI;
			$T.RadTileList.prototype._onTileClicking = function (tile, args)
			{
				var eventArgs = new $T.RadTileListCancelEventArgs(tile, args.get_value());
				eventArgs.set_cancel(args.get_cancel()); //the change - pass the _cancel argument to the TileList handler too
				this.raiseEvent("tileClicking", eventArgs);
				args.set_cancel(tile._isDragged || eventArgs.get_cancel());
				args.set_value(eventArgs.get_value());
				tile._isDragged = false;
			}