The lessee. Early on a lot of unhappy people damaged the meters - you don't have to pay if the meter is broken. They learned from this and the current meters are very robust.

It only takes a can of spray paint, one need not bring a hammer. But now that it's all mobile-enabled all that doesn't help as much as it once did.

Point taken :)

It appears that spray paint is still illegal to sell in Chicago - obviously nobody has it. Right?

https://codelibrary.amlegal.com/codes/chicago/latest/chicago...

Robust to thermite? Asking for a friend.