It wasn't easy to geofence due to fluid nature of the frontline and lack of single official supply channel to Ukraine. A huge part of Ukrainian terminals were also procured abroad by volunteers.

However a recent development was Russian use of terminals on attack drones. Out of that Starlink was able to block terminals with certain velocity (and possibly bearing) in the region. In addition Ukraine got around to making internal registry of all frontline terminal allowing Starlink to white-list. So no it was a bit more than a tweet involved.