[takno]

What would generally happen if you tried that in a place that stated they didn't accept tips in the UK would probably be that you'd be smiled at, your money would go in a charity tin and the server would make a mental note to serve you last next time. I suspect your ego would then simply reject the obviously bad service you received the next time and you would convince yourself that you had somehow benefited rather than accept that your previous actions were arrogant, culturally imperialistic and unwise.