The reminds me of an incident that made me (kind of unfairly) boycott Bed Bath and Beyond for the last few years -- I lost my wallet and didn't have credit cards for a bit, and when I tried to pay at BB&B with a check, they used a machine that told them I was too much of a risk, though I had an 800+ credit rating and thousands in my checking account. I complained and researched and eventually realized that basically all retailers use this check verification system that uses AI that considers your checks too great a risk if you don't normally pay by check -- so the idea that you can use a check in an emergency is really an idea from the last century. This bad decision by eBay seems like the same sort of thing -- machine learning teaches the AI that people who don't regularly buy and sell are far more risky than people who do (which of course they are), so new or occasional buyers/sellers look like a huge risk, and get randomly bounced.