As a giver of one of these notes, I would imagine you have decided to stand against bribery no matter the outcome of the scenario where it is given. Hopefully reason wins out and the situation ends amicably. To address the bribery problem, though, there’s a sense where you have to be okay with things getting worse before they get better.

It seems to me the note is a socially well known form of protest, which may go down better than a direct interaction.