deus.ex.machina wrote: The tax office probably thinks so too ...
Once upon a time in "Rock Radio", if I remember correctly, there was a discussion whether waiters / waitresses should account for tips as income, despite conversations with lawyers and several phone calls to the US, it was not possible to clearly answer the question.
At one point the listener called and said that he was a pizza delivery man and he often delivered to the US, every time he gets a tip he has doubts

whether to accept, because after all it is the Tax Office, and the amount on the receipt is the amount on the receipt ...
Let's not get paranoid.
Ps.
I found an abandoned 2PLN in a shopping cart. I couldn't find the owner, so whether I wanted it or not, I got rich. How should I put it in next year's settlement. I must admit that it happened to me 3 times this year, and I found a zloty again, all in the same shop.
Greetings.
CMS