Is it dangerous to serve user-uploaded Flash (SWF) files?

I'm working on a site that has CMS functionality. I'm considering allowing users to upload Flash (.swf) files and then displaying them on my site.

• Is this a bad idea?


• Is there a way to do this safely?


• What are the worst things that can happen, both to my servers and to visitors of my site?


• What precautions can I take to mitigate these issues?