Anecdotally, I've worked for various companies in NY and VA and had IP agreements. I even was given a compulsory IP agreement when I tried to volunteer for the Red Cross, which conflicted with the compulsory agreement with my employer.

For me, it's a significant attraction to working for the government - if I'm not in the office what I write is presumptively mine; while I believe at the state level anything I create at work is not public domain, I don't remember any IP agreement beyond the ordinary work-for-hire relationship.