Direct to miner solutions prevent those tx's from being gossiped to avoid this.
Discussion
How would you prevent it? If company A pays MARA to mine a certain txn, then Company A also broadcasts the txn, what would hinder that?
Company A is incentivized to broadcast as well as work directly with MARA. Then MARA would be on the hook for an invalid txn included in the block. But if MARA wins the race, Company A still gets included.
RTFM for slipstream.
Lol, I literally just did, there is no carve out for broadcasting the transaction as well as using their service. So, I mean what are you referring to exactly.
It pays 2x fees at a given time and is primarily for non-standard transactions with guarenteed block time within a day. Relaying those don't happen because policy. Someone could submit to another miner and nothing stops them but right now there aren't many offering slipstream like services.