BAD IDEA
Can I leave the mall food tray on the table claiming I don't want to take people's jobs?
No, leaving your tray as a 'favor' to staff is just inventing busywork and gross behavior.
Leaving your food tray on the table because you 'don’t want to take people’s jobs' is a bizarre excuse. Staff clearing tables isn’t some endangered species; that work exists whether your tray is there or not. Just clear your mess like a decent human and save everyone the awkwardness.