Let's say that someone moves a Tor instance  from one internet access point  to another one. And let's say that an adversary is logging traffic from both access points. The adversary could log, that some user Tor client has chosen X entry guards out of Y available entry guards.
How unique is that Tor instance's set of entry guards?
When the user moves to another internet access point, couldn't the adversary be pretty sure, that it's the same user?
This is getting problematic if the adversary can at some point link the identity of a specific user to a set of entry guards, because the adversary can now monitor from which location this user connects to the Tor network?
Would it be better to have a separate installation of Tor (and therefore set of entry guards) per internet access point?
: For example an installation of TBB on a flash drive or so.
: Different ISP's, WiFi hotspots, VPNs etc.