I recently had a MUC-LHR connection onto the last flight to GLA. MUC-LHR sector was delayed and I was convinced I'd be overnighting at LHR, but somehow managed to get through immigration and security at T5 connections (though I was sure I was outside the MCT). Ran to the gate where the flight was boarding only to be found that I'd been offloaded "as the computer assumed you weren't going to make it". Gate agent simply reinstated me into my original seat which was a relief (no checked bags though, which probably helped).