The 1737 Thieving Slang Dictionary lists "tip" with the example sentence "tip your Lour or I'll mill ye," which means something along the lines of "Give me your money, or I'll kill you with this woolly-mammoth tusk" (OK, we're not sure what weapons they used). The word eventually acquired the meaning to give a gratuity, apparently after someone had the most terrifying waiter in the history of the service industry.
There's a reason waiters keep one hand hidden when handing you the check.
What we're trying to say is, 200 years from now, educated people will be using gangster rap slang in everyday conversation, and they will have absolutely no clue where it came from.
"My dearest ho, I believe my bling has slipped out of my pants. How pimp of me."