One of the famous American Express mass-shutdown events was caused when gamers paid AmEx with an AmEx through the now defunct PayPal Key and a becoming defunct bill pay service. Similar shutdowns happened at Citi when a credit card bill was paid with a Citi card, and those definitely aren’t isolated events, they’re just prominent.

I intuitively understand how people get themselves into this loop, because when a technique is simple and easy, your mental load is lower and it’s easier to push a big volume with just one or two moving pieces; The flip side is that it’s also much easier for a bank to figure out what’s going on and directly tie your activity to shenanigans.

So, avoid the death loop and always use an intermediary when playing games with a bank’s rewards earning card. To stay alive, never pay a [bank] with a [bank’s card].

“What about this one?” you say, trying to catch me in an edge case. Look, it’s simple. Never pay AmEx with AmEx, sorry.