Outside of California they might be ... hindered by non-competes. I was once in this position: https://news.ycombinator.com/item?id=6148918 and one of the many reasons I didn't accept the offer was that non-competes were enforceable in my state, the contact had a nasty one, and the acquiring company did business with so many of the area's organizations that I would have been seriously disadvantaged when it came time to separate.