Originally Posted by
ArchlordPie
Pretty sure the Z axis didn't actually exist in a lot of ARR zones until recently. Kind of hard to implement a check for a variable that isn't in the game in the first place.
That being said, WoW can and will automatically disconnect you for existing under the map. I found out because I found a literal square hole in the ground in the spooky BFA version of Vale of Eternal Blossoms a couple years back. Flew right in there while mounted thinking "wow blizzard's QA team must suck if they left this thing in, let's go exploring", and immediately got sent to the login screen.
Nowadays... yeah. SE needs to step it up.