Time to penis is not just for software and game dev, applied to physical mediums long ago first.
I'm seriously saying that the institution of Christianity is well known for housing and protecting pedophiles.
It's generally considered rude partly because of the possibly of food falling onto the ground, and also because it would incentivise the person to just drop the garbage after they're done eating whatever as is often the case in America and Canada.
When food carts are set up they generally have garbage collection nearby of some sort. That said staying in one place and eating is approved of more. If you're a foreigner you will get looks but a free pass in the sense of "ah we can't expect a foreigner to ever understand our culture and expectations" which is a pitying position from what I've experienced here.