I guess that my new logo is questionable. I am beginning my company based on repairing Amigas and tried to make the logo reflect it, however, since I created the logo, I did make sure that if it becomes necessary, I could, in fact, remove the boing ball... Layers are our friends ;-)
I feel that because I too want to serve the Amiga community, that this is probably fair use, but if anyone ever challenges it... I have made concessions.
BTW: For those of you who have been following, we have decided to make our company Non-Profit :-)
I still don't think anyone should "nick" the logo from someone and claim it to be their own. IMO - A.org's logo is a derivitive work and as Wayne said, it is used with documented permission pre Amiga Inc, so that will hold up because the permission was granted in writing by the former copyright holders. There would be some kind of "grandfather" situation there.
Anyhow, I think all reasonable legal means should be exhausted before people take the copyright laws into their own hands. Amiga software, for example, is sometimes hard to track down an owner of the copyright because the project has been abandoned (in some cases many years) ago -- so while it may be technically illegal to "pirate" this software, there is no legal means to license it. This doesn't make it right (in copyright law's eyes) but at least there was probably no other way to obtain license legally. It can be a very grey area.