When autovivification is mentioned at all, it is to rave about its (undeniable) virtues, i.e. the Good. It's as if we are so eager to encourage the tremulous newbie to try riding the bicycle without the training wheels, that we don't want to dampen any enthusiasm with talk of potholes, and semis.
My experiance is just the opposite. The first time I see most new Perl programmers run into it is when it causes some bug, which causes some (understandable) complaints about the feature.
I do wish exists was special cased to not autoviv a deep element when a shallow element doesn't exist.
"There is no shame in being self-taught, only in not trying to learn in the first place." -- Atrus, Myst: The Book of D'ni.