For the record, a few of us have attempted and managed to recreate Wyvern aggro taking the exact same path Bruize did in his video -- by enabling sneak at the same spot, and disabling sneak at the same spot -- and aggroed wyverns at a 100% success rate.
Over the course of two incredibly boring hours sitting in ToV, we attempted it a total of 37 times by sneaking where he started, and dropping where he started. Out of 37 times, we aggroed the wyvern trap 37 times.
This post is for the <Awakened> members that somehow think Bruize did not aggro those mobs. Bad luck on being the one to lose the wyvern lottery, but it's still your responsibility for them being brought to where they were dropped and what played out.