Hey!
WiFi hotspot with WPA-2 Enterprise users log in via FreeRadius. Everything works great.
And how to determine when the user disconnected from WiFi? WiFi hotspots are the easiest...
The simplest way is to write a script that will poll the point on a timer.
Another way (if the point is not easy enough) is to run a similar script on the point itself and send messages from it.
Answer question: why WPA-2 Enterprise if it costs freeRADIUS?