I too am concerned to read John's post. When I called in at Llanrhystud at 9 yesterday morning there was also a couple with a large camera following the Wryneck (but they may not have been the same people). The bird showed distantly on a post-top, then promptly vanished and I didn't see it again.
I think it would be a great shame if we were to have to stop putting these birds on the blog due to the actions of a small number of individuals. Can I suggest that as a start, it would be good to add a warning on the post in situations where we judge that this may be a problem - as they sometimes do on Birdguides (e.g. for the Gwent Marmoras warbler).
The other action would be to take the step of speaking to individuals who we see indulging in unacceptable behaviour of this type (as John did in this case). I suspect that it's often primarily thoughtlessness, and a polite rebuke from other birders might make them realise the foolishness of their actions. If not, at least we've tried...