OK. I've been messing around and trying to twink trial accounts for the level 19 bracket to see if it's actually viable. Using my level 80 Priest, I have been grouping with my trial account characters for instance runs and item farming.
Anyway, about two weeks ago, I cast levitate on my trial account Priest and jumped off the top of the ramp in Stormwind to catch a boat in time. When the character landed, they got the "Going Down?" achievement. Fast forward to today and I cast levitate on my trial account Pally and ran her off the cliff overlooking Wetlands and they got the achievement.
I don't know if this is a bug or what. I've heard in the past Levitate doesn't work for getting achievement.
Even stranger is the fact that trial account characters can group with my level 80 when the trial account restrictions posted on WoW's website says trial accounts can't group with characters over level 20. So that might be a bug in itself as well.