Wow, they're using USDT? Lol. Nobody tell them that Tether can freeze their coins at any notice.
I'd prefer if they stay far, far away from BTC and XMR.
Most of these donors have no idea how blockchain works, which is great because the more they stay away from us, the better it will be.
But even if the used the two blockchains, nothing is going to happen to them anyway. The services that will suffer are probably the centralized exchanges that would received the coins but just like hackers, in most cases such funds are first mixed or passed through bridges before the hit an exchange. Someone is definitely going to have this in their mind in the near future if the sanctions press hard.