Should insider trading be legal?

[MaC]

This brings up another question...if you get an insider tip, should you take it?  I can't say that I wouldn't..

aren't people who get this information only acting within their own self interest? 

Better yet, my concern with the legality is:  How can you tell if someone knows something or not, you'd need some kind of mind-reading to be able to tell if they actually heard this information, or it's coincidence.