So far, I've played AL modules only at cons, and my attendance there is 100%-dependent on saving up the money beforehand.
My FLGS experience with the APs (HotDQ / Tiamat, now PotA) has been that the campaign slowly migrates away from AL standards over time.
I haven't tried to run mods at FLGS; when I finish DM'ing Tiamat (or talk somebody else into it while I work a seasonal job), that will be an option I bring up.
Therefore: getting out of a 'one-way gate' module by playing another specially-designated module later, will be very difficult for me. I will decline the module, rather than tie up my character for months of IRL time.
The best way to handle this is to have "Part One of Two" / "Part Two of Two" as part of the module ad write-up, and schedule them right after one another.
Think of it as getting stuck in the on-ramp to a Toll Road (or a limited-access Interstate Highway) due to congested traffic; the way back off the Toll Road may be an extensive DETOUR from where I really wanted to go.
