I think just keep original fee and deduce 12.3% btc balance from all accounts until stolen BTC is covered (in 2-3 months). So the exchange will self-recover with the help of all users and no one lost BTC.
+1
A fee increase to 1.5% would likely be self-defeating in that volume would fall drastically. Keen to hear dev's estimate on pay back schedule, based on current earnings. I think he owes us that much...once he's had some sleep
