Working at a LFS, I have heard of all kinds of things that people do with damsels. Usually we tell people up front that damsels have the potential to be aggressive and that they can bring them back when/if that happens. Sometimes, I'll recommend not going with a damsel for a starter fish but people generally don't want pay a whole lot for a fish that is going into a newly cycled tank and may or may not live. Personally, I have never owned a damsel (excluding clownfish) but I don't think I could ever flush a fish, no matter how aggressive. A friend of mine had a damsel that lived in his sump for quite some time. (sorry for the ranting).