It depends. I don't think bad of any of my coworker who went on PTO and gave their notice on the Friday before coming back. What I remember of them is how great they were. This little snag at the end is just people being human, having had enough and not wanting to get screwed by a company's HR department. I'd recommend them anytime and they never suffered from it either, many even being hired by startups created by their ex-leaders.