If someone picks it up you will get a console error. I would advise finding a method native to Blockland.
But the item fading part? I still think that finding the native solution is the way to go.
there will be no console error, if you delete an object with schedules on it, all the schedules are cancelled, which is basically the same as picking up the item
this is what I would personally do:
%item.schedule($Game::Item::PopTime-200,fadeOut);
%item.schedule($Game::Item::PopTime,delete);
it might not be the best method though