Not really, even at my work we have (well, had) regular swap-meets for supermarket discount trackers. So one week I would shop as badge #1, the next week I would be badge #2. Just knowing the identity of the person who was issued the account doesn't give you any information about who's using it now.
In aggregate, you would still be able to identify which group of people used which endpoints, but aggregate information won't hold up in court.
Yes, geolocation would solve that, but I would expect such people to absolutely disable the GPS, so you'd need to rely on cell tower pings, which are not found on the same servers.
Even end to end encrypted systems know who is talking to who, and how often, and where those two parties are (due to client IP geolocation).