On purpose, I avoid the topic of publishing the footage altogether.
In the flight deck, it's what you do with it as opposed to how modern the device is. The DLSR camera case makes a strong point in that direction. The industry already has
operationally approved dual-suction mounts holding 2kgs EFB sets, and they are verified for de-compression. No issue with GoPro cup technically.
A reasonable approach would be to assess the phenomena, highlight the risks and provide guidance - where necessary in the form of restrictions. Not to ban it, not ignore it either.
And my issue is the distraction. Attention-wise, the mental one. I've done a lot of EFB implementation work some time ago and was the geek guy for years. The passion for technology is still there, yet these days I seriously contemplate the idea of turning my personal phone completely off check-in to check-out. For clarity of mind when aviating.
FD (Not an owner of a GoPro, but already experienced unhappy thoughts seeing colleagues fool around with them. As well as calling some others the day before to make sure they'd bring it.
Life is pretty.)
BTW: thanks for the comment on opening the doors to a filmed flight deck.