Anonymous user record being updated

The following explanation as to how this happens has been provided by Support when fielding help tickets inquiring about this issue.

There is nothing inherent about the customer account that is used for anonymous shopping that tells Tessitura or the API that it is in fact an anonymous or dummy account.  As far as Tessitura/the API are concerned, it is a customer account like any other customer account.  This means if a session is logged into that account while the customer is shopping, nothing at the API or Tessitura level prevents changes from being made to the account.  Any recognition of these accounts as being anonymous and, therefore, any preclusion of accessing or updating the account information needs to be enforced in the web site code itself.  Often web vendors add logic to check to see if the customer number tied to the session is the anonymous account and if so, it prevents the customer from being able to manage the account and instead takes them to the customer login area.

We have the same issue, and we've been trying to track it down for years. I've discovered essentially the same thing as Nathan, and that is that the session seems to get "lost" and the site gets mixed messages about login status, and anonymous status, essentially thinking that the anonymous user is a normal user. 

Did you guys develop your own ecommerce sites, or was it developed by a vendor? I'd be interested in continuing this discussion if someone finds the actual issue.