I find it easier not to worry about it and simply to check back occasionally.

I have yet to have a flight that I have not been able to check in online before my flight.

Sometimes if the itin includes a partner (such as LH) I check in on the partner if their flight is earlier (using the partner website) then when the AC flight is available I check in with AC.

... in end the I do end up being checked in and it really is not a major crisis as long as you can check in at least a few hours before your flight ... the goal after all is to avoid the b*stards at the the checkin counters forcing you to prostate yourself to checkin!