logon hours AD setting not applied when not on network

i set the setting in AD but my kids wake up in the middle of the night and unplug the NIC then they can log in... yes they cant access the network drives but they can play games and what not.

any ideas?

more data

log off after logon hours GPO was set but it only disconnects SMB sessions (file shares)

I have a script to shut down all workstations and laptops at bedtime