Several VPN applications check for a correctly configured endpoint as a prerequisite to join the VPN. This can involve enforcing OS, OS updates, AV programs, etc. depending on how your system admin has set things up. In such a company performing an end run against this check can get you into trouble
Interesting. I'll have to add that to my list of questions to ask companies in an interview. Not being able to use Linux is a total deal breaker for me.