Ha! Today I waited until the last minute of the 24 hour wait before accepting a negotiation offer. I did this simply because the manager had offended me with a 0 token offer in the past. Petty, I know, but I hope that during his 24 hour wait for my reply he bought another player for the position and now has a surplus.
If buyers are going to get the option to withdraw an offer then sellers should receive a compensation of for example 1 token. This only payable once the selling manager has acknowledged the offer. Not accepted, acknowledged.