We never even went to Grakelstug. We found our loot at the conclusion of Blingdenstone. Some of our DMs took to replacing random magic item rewards with non-random magic item rewards MOVED from other parts of the adventure. Early groups that skipped ahead or went really fast through the modules get to keep their randomly rolled, cert-less magic items. Maybe some GMs think that is unfair and arbitrary? Most players are not going to complain when a DM hands them a cert. Especially if they've never read the module, or are one of the majority of players who have never seen the AL FAQ. We can't be the only place where people did something like that. If they made certs it must be OK to be in the module, right?
If you build it...they will loot.
If you build it...they will loot.