[EscapeFromNY]

I didn't downvote, but it's probably because of the lack of understanding and/or fear-mongering around privacy/anonymity.

Yes, he'll have to report the donation and pay his taxes. Yes, someone may "take a close look". No, there is no chance he'll be legally prevented from accepting the donation, unless he lives in an authoritarian country like China/North Korea where owning crypto at all is illegal.

Crypto has been used for anonymous donations as long as it's existed and afaik nobody has ever faced any legal problems from accepting an anonymous donation. https://en.wikipedia.org/wiki/Pineapple_Fund

[newaccount74]

If you live in Austria, the very least the Finanzamt will demand is that you pay 16.7% of the amount as VAT, since you can't prove that the payment is VAT exempt. If you don't declare it correctly from the beginning (eg. because you assume it is a payment from a non-EU country that would be tax exempt) you will face a fine on top of it.

If you get caught up in criminal investigations, eg. because you previously worked for a company that was caught paying people under the table, you will have no way to prove that the donation was legal.

I wouldn't worry about anonymous donations of a few hundred Euros, but a 100k anonymous donation will definitely invite a close look from authorities. In my experience tax audits are stressful enough even if you did everything correctly and have documentation for all payments.