Its drastically worse than a Burn book as the kid is holding the device and it reamains there for them to see everytime they open their phone.
There were two times I heard of parents bringing in lawyers.. over the same situation my child was going through. I am sure this is gonna happen more and more.
Also kids are somewhat wise to not mention names and be vague enough to not be identifying the girl, yet if you are close enough you know whom they are talking about.
Thats was why i started getting daughter into other social medias, because she has phone in hand all time and wanted her to know there are there are other social media outlets. I think it allowed her to not have it as hard.