How do you do it? I've been using Trustwallet for a long time and I haven't seen any USDT mining notifications on my Trustwallet account. Moreover, as you say, they even give a fee of up to 8%, I think that's a big bonus, are you committing fraud?
He might be the one who will mine in your TrustWallet every time you deposit pretty bad he is the only who will mine not us.
Unless he mines altcoin auto converted to USDT? You can do that on ViaBTC pool.