So, in the Account section of CIU, you can only have one guest account normally, and the option to create a second one is greyed out. I’m not sure why this restriction exists. I asked and someone mentioned that having too many just spammed the server.
Anyway, it turns out, if your actual account with a linked email gets removed due to inactivity, the guest account made that ties into it stays behind. And, once you link a new account, you now have the option to create a guest account for that one, which in turn actually allows you to have multiple guest accounts.
I don’t know if this is actually that big a deal or even worth looking into it, but I wanted to mention it.
Thanks for reading!