It's come to light that cameras were installed in a maternity unit in Cambridge and women were filmed while having scans without explicitly having been told it was happening. It seems this was because the film company was making a documentary about stillbirths and were hoping to catch people at the moment of being told their baby had died. At that point they would be told they had been filmed and permission would be sought to use the footage.
www.mirror.co.uk/news/uk-news/parents-horror-after-hospital-secretly-11606165
I understand it's important to raise awareness about stillbirth, but surely a note next to a camera isn't adequate when it comes to consenting to being filmed at a time you'd assumed would be private?