Many, if not all, of the various restrictions I've seen put into place were done in reaction to a legal problem. IM gets banned because someone leaked a secret. Websites get blocked because of a rash of sexual-harassment lawsuits. On-access virus scanning because on-demand scanning didn't stop the last worm. It goes on and on.

There's a natural friction between developers and infrastructure. Developers consume the limited resources which IT has to manage. I've done plenty of both, and basically, both sides are correct. I recommend working on the "other side of the fence" for a little while to anybody in the industry.