Thanks for all the feedback everyone!
My intention was not to start a debate about the pros and cons of one framer/store over another. To clarify, I was looking for some feedback about methods of proper storage. For example, is simply placing the poster in the frame (loose) OK, which is what I currently do, or would it be better to mount it on a border mat with archival tape to prevent the edges (specifically the bottom) from being rested on?