I recently was returning from a conference (no way to check-in online) from San Francisco and checked in 43 minutes prior to my flight, and they would not let me check in. They stated that they have a 45 minute cut-off, and we had to wait 9 hours for the next available flight. Is this common now, or was their potential that the flight was full and they were looking to bump people, and could use this rule? I fly a lot, and never had this happen, but can generally check-in online prior to going to the airport. If I had checked in on-line but still had bags, would this have happened anyway?