A Game Master confirmed in chat linked by Redditor KazmaticsTV that getting atop buildings to avoid guards in PvP qualifies as terrain exploitation, which can lead to warnings, and possibly, suspensions.
Image courtesy of Redditor KazmaticsTV (Source)
Another post dealing with the same subject has amassed 15.2K upvotes so far and was written by Redditor BussyBlastBismallah who reported a person in Gadgetzan for using the exploit to kill people and was for some reason contacted by a Game Master who issued a warning, because the player was apparently indulging in exploitative behavior too, based on player reports.
Image courtesy of Redditor BussyBlastBismallah (Source)
The roof camping problem was fixed when Blizzard added a Gadgetzan Sniper in the Burning Crusade, as pointed out by Redditor Eredun. You can find his suggestions to the issue here.
Would you like to see the NPC added in WoW Classic despite the fact it wasn’t present in Vanilla? Let us know your thoughts in the comments!