The only way I have been screwed by mms is when I put in a market order (trying to get less brokerage). Big mistake as the MM actually adjusted the offer price before taking it.
Just last week I put in a sell for 80k when only 20k was on offer. They were snapped up on the instant and another 100k appeared. And this was on a serious loser with the market against me. On the other hand, if the market is going your way - they will beg you to sell.
It's possible you could get caught - but if I run into a MM like that I would pull the bid.
ETOs are a different matter - the MMs are sneaky bastards and all kinds of tricks go on. On the other hand they can be psyched, unlike warrants where it is computer-run.
By the way, how to you find the phone numbers for warrant issuers? I have never rung them, though I have often wanted to, regarding spreads.