I think I had the opposite situation happen. I thought I would miss my connecting flight on SYR-EWR-LHR due to delays. At SYR I had myself booked on the later EWR-LHR flight while protecting my original flight. I arrived at EWR at T-3 for the original flight so I assumed I had no chance of making it and just went straight to the later flight. When I tried to board, I found that (essentially) the GA for my original flight assumed I would make the connection so cancelled my BP for the later flight. There was exactly 1 no-show, otherwise I'd have been stranded overnight. So it works both ways with tight connections.
Or at least it's critically important to know the difference between protection and standby.