I voted No.
Why on earth would any teacher consider adding students to their own facebook?? That is very odd for me personally.
Maybe i am a prude.
It is not about evidence at all, it is all about moral boundries/responsibilities and respecting a young persons privacy in knowing they are vulnerable and about keeping them safe.
I have school age volunteers. They are a big responsibility personally. There is no way on earth i would put them in a vulnerable position even if they agreed to a photo let alone facebook!
They are most certainly an inspiration for me, the younger generation is awesome in so many ways, though my goodness we need to care for them, protect them and keep them safe.
"There is enough love and concern for animals in every community to overcome the irresposibility of the few"