Actually, Monero guys did it on exchanges in the last year. Especially on Binance, they withdrew their funds from exchanges in the same day, proving exchanges don't keep their funds in reserve, pretty much all centralized exchanges are working same like banks (not a coincidence banks, big tech, gov funds own the majority of crypto exchanges). Binance even halt the withdrawals for a while... :) :) :) They called it Monerun, unfortunately the official site is not live since couple of weeks, but you can find it, even on Hive.