Quick buy and quick sell is still your own choice, you can wait untill you get a decent offer or you can sell right away for fast cash, I used to be a high end trader and sometimes it can take months to sell a unusual for the fair price so some people sells it cheaper.

Personally i never did quick sell unless it was to stock up again, I do also know tho, if a quick buy offer seems more like a sharking problem then it is just to report it and the mods will look into it, had that problem myself a few times ^_^

So all in all it is just your choice to tell them to either fuck off or say yes ^_^