If you are out to get the better of someone via a trade, then sure you don't want them backing out once you've hooked them. Personally, I wouldn't want to make a trade like that. If I traded with someone and they afterwards felt the trade was one-sided, I would trade back. The exception would be if some event occurred after the trade that changed the players value (e.g a player announces retirment or has a serious injury).

If you are making one sided trades, eventually you'll find few owners interested in trading with you.

At least I hope so.

DaveF