Many crypto exchanges impose quite low limits on withdrawing balances from their sites. For example Binance has an equivalent limits of 100 BTC for a daily withdrawal.
The question is, why do they need to impose a limit at all? Are the customers coins not in segregated custody, and when sold in a transaction on the exchange, the funds should be there irrespective of the size of the transaction. In short, why would an exchange need to limit withdrawals at all?