How is a go-pro more damaging than my kneeboard, charts, pens, calculator, phone, torches, life rafts, life jackets, portable radio, spare headsets, bags, fuel, DSLR camera, iPads, GPS trackers, strainers with sharp bits including all other loose item in the plane?
I expect that if you read through the regs (that is if anyone had the time or a brain big enough to remember them) it states somewhere that everything in the aircraft should be tied down. So in CAA world they are not specifying anything very odd.