I’m curious as to whether this issue is limited to just Timezones, or if this is just the most common manifestation. Wouldn’t you equally want an alert if the Timezones matched but the dates and times configured were vastly different - eg. if someone misconfigured or never configured the actual date/time on their server or client device?
Might an alternative be to just ask the server for the current datetime (in the form of timestamp in ms) and compare this to the current datetime on the client? Then you can make whatever decision you need to make based on how closely these match (eg. within a few minutes of each other is ok, but more than X time apart is not ok).