Don't know about USDC, but USDT almost instantly locked the funds, making them unspendable.
The USDT will be burned and the USD released to the rightful owner after law/legal approval -- https://twitter.com/paoloardoino/status/1425188386034311168
I d propose every chain to have a blacklist mechanism, temporary if you want, with a voting mechanism to remove innocents. You cant facebook your way ("we re just a platform") out of financial rules or you ll just end up rewarding thieves while benefitting innocents very little.
That's why decentralized stable coins like DAI and others exist :)