How do you see which AU are currently on your BoA account? I have a different AU I've added that should still be on there, but I don't know how to verify that. Hopefully they didn't just remove this AU without my request like they did the previous one. I suppose I could call in and talk to a rep, but I'm afraid that would be suspicious and also I'd sound like an idiot for not knowing who my current AU are (even though I know who it's supposed to be).
Interesting! I understand your reluctance to call and ask suspicious questions. I agree that it would be better to find out another way.
I don't see a way to find out on the BofA website. (Some of the other cards have sections where we can manage our AUs, but BofA doesn't even provide good results for info in their search bar! "Authorized users" or "add user" search terms return results like "What is Twitter?" HA! Useless.)
I would send an email to the TL company and ask how an AU could have been removed. I wouldn't think the TL company could do it, or would do it, and would find it very difficult and rare for an AU to remove himself. The TL company is a good resource for these kinds of questions.
Also, the TL company runs credit reports on the buyers (to confirm the add occurred or didn't occur) so they will know which of the AUs were on the card as of the date of their last credit reports (IF it shows on the credit report).
If you do decide to call BofA to be sure, maybe you can call and say you want to confirm that an AU is still on. If they say "No, would you like to add him back?" ask if he was able to remove himself and say you will chat with him and find out if he removed himself and get back to them.
Frankly, I wouldn't bother. I would just communicate with the TL company to get as close to the perfect answer as possible. If the card wasn't on an AU's last credit report, it doesn't mean he's not still an AU on the card; it just didn't report correctly (yet). But if the card WAS on someone's last credit report, then you know he was an AU as of the last closing date anyway.
The rarity and difficulty of an AU removing himself wouldn't make it worth my while to investigate to the nth degree.