[defaultname]

In most places the onus is on the police not to accept free food. It is their professional duty not to take free items. Because it starts to smell a bit like a protection racket, even if originally people offered out of true generosity/thankfulness.

[bdcravens]

I think you may be right that's it's less a legal issue than a self-policing issue.

Not doing so does have the risk of devolving into corruption. Here's an example of it going too far that direction, where the police arrested everyone for not giving them free food: https://www.cnn.com/2021/06/16/asia/pakistan-police-detain-s...