There are a dozen different factors that come into play with who receives the check first. The waitress porbably doesn’t even remember who came in first if it was busy. More than likely, the “white” table finished the meal more quickly, or the “black” table had extra drinks or dessert. It could be something as simnple as the “white “ table was closer to the waitress station.
The only people perpetuating the stereotype are the cheapskates who assumed the worst.
Or, the white customer could have requested his check on the way back from the men’s room or whatever.
The concept of taking slight because a party seated after one gets a check first is pathetic.
Simply an excuse for a cheap bastard to stiff a waiter, while preening on some imagined moral high ground, on Valentine’s Day.
Period.