Mostly I look at friends in hardware infosec who have not _that_ much fancier equipment than me on their bench, and routinely pull BGAs off boards they're analyzing, mess with them, reball and reinstall them with surprising ease. I'm sure it's a very acquired skill, but... Not impossible?
I'm told the secret ingredient by far is a board preheater, in addition to the hot air gun. But again, all hearsay.