A few years ago, I booked a 13:45 PHL->Canada nonstop on Avios at 12:33, while I was still at home, unpacked (~15 mins from the airport). I thought I'd be able to OLCI, and with PreCheck I'd make the flight no problem. Except there were no non-premium seats available, so AA wouldn't allow OLCI. But I had AB Gold (OW*S) status, so I should be able to select premium seats... Except the website wasn't letting me change my FFP from BA to AB. I tried calling in, but the agent couldn't do it either. My last-ditch effort was to toss some clothes into my backpack, grab my passport, and run to the curb to grab a taxi ~12:50 (after check in had closed) to get to the airport. I got to an agent around 13:05, and they actually checked me in and let me on the flight! And I had PreCheck, so I made it to the gate before boarding even started

Forgot to pack pants for that trip, though