It is quite common for there to be a 4 hour limit on how early you can check in for a flight. And flying *A doesn't completely solve this.

I've had to walk around HKG with all our bags for several hours before being allowed to checkin (arrived on a cheap, upgraded AC YOW-YYZ flight and was leaving much later in the day on a *A RTW fare.) At least at HKG the pre-security airport is interesting with all the stores in the new terminal. The only advantage *A had over another airline in that situation was that once I could check in, I was able to use the Exec lines so there was no crowd in front of me.

Another time I arrived in Rome on AC and was connecting to a Europe Airpass flight. Had 6 hours (was supposed to be 8 but AC was late) and checked to see if LH could check us in. They couldn't on our existing flight but did check us in for an earlier flight at no charge.

This year, the advantage of *A all the way has finally started to prove itself. On our last two flights (four itineraries) the originating airline was able to check our bags all the way through to our destination. And then, because the bags were already checked, we didn't have the 4 hour restriction on getting our boarding passes when we were at the connecting airport for our DEL-FRA-CPH flight and SAS actually was able to print off the boarding pass for FRA-YOW when we checked in at CPH. She was rather surprised she could, though!