People are going to camp regardless though. I understand it helps them, but if people already use that playstyle radar on or off wont stop that.
Its as simple as the boltshot thing, runnging around a corner carelessly gives boltshotters and campers the advantage, regardless of radar or not.
Play smart.
I like radar because being in a firefight, a quick glance in the corner can give vital information on whats happening. How many ememies your facing, where your teamates are, and most importantly if your getting flanked and an assassination is looming.
Edit: Id also argue that no radar would indeed make more people camp and corner hug, waiting for people to run by and then score an easy assassination. Radar does more good than bad.