I don't understand how things work in the US in terms of transaction of cryptocurrency, because if it's about tax invasion or the owner of the cryptocurrency doesn't want to pay tax or supposedly doesn't want to reveal the history behind his crypto transactions, is there no P2P options that are available with exchange companies within his country, at best you can only pay the charge for using their exchange services, because P2P will just have to pair you with an agent that will pay you the equivalent of Fiat that you need into your Bank account, instead of running around the globe and going to Philippine and looking for charity to donate to before getting back your money.
P2P doesn't save one from getting away from being tax. If IRS want to do their investigations about tax fraud, anyone involved will not escape it because of KYC has made the job easy for them. If for instance User A has invested in Bitcoin and send then convert that coin into another altcoins, a time will come that he is going to covert it back to stable. If he decide to send that coin to p2p for sale, he is going to be required to pay tax on capital gains because it's easy to do that with KYC, p2p doesn't save anyone ass from tax evation.
The only means you can evade tax is if you run your p2p on a decentralized exchange where you don't have to do any KYC requirement and transaction are purely base on agreement. As long as there is no coin sale reference on your payment, you absolutely have nothing to worry about but you know as they say, 99 days for the thief but one day for the owner. It's better to pay tax and avoid aby future problems in your finances, any culprit caught evading tax don't end well.