Maybe, maybe not. There does seem to be a built-in grace period of at least 15 minutes past the window that we've been in without comment or intervention from a CM. In December, due to a transportation issue, we were nearly 15 minutes late for one of our FP+s, and the CM said, "You had 37 seconds to spare." One other time, we actually arrived early for our FP+ window (I thought our window was 30 minutes earlier than it actually was) and to my surprise, the CM overrode the blue Mickey and let us on. That was on Peter Pan, in the afternoon, when the SB wait was posted at 60 minutes. I was surprised that he didn't make us wait, but he said "No problem" and let us on through. He had to have done something in the system because at the second touch point the Mickey went green without the CM there having to do anything.