There are various linguistic constructions you can use for plausible deniability (e.g. "at home I can just pay a fee to get into a different priority group: do you have the same system here? I think I have enough cash to cover it.")

I actually once did pay a speeding ticket to an arresting officer (in Montana or Wyoming or one of the Dakotas IIRC -- it was decades ago) an it was very clear how the officer handled it that he was not pocketing the money (e.g. he held an envelope I placed the check into, I licked and sealed it, and his boy never came in contact with my check, though cash was also an option).