This was widely reported in the press here...
www.irishtimes.com/news/consumer/family-felt-sense-of-danger-after-finding-hidden-live-cam-in-cork-airbnb-1.3850498
We stayed at AirBnB in Austria a few months ago. The host proactively let us know in advance she had security camera system in place, locations, etc. We knew in advance, and it was our choice.
However, this hidden camera stuff is kinda scary. It seems to be a legal grey area in some countries in Europe.
Going forward I think I'd explicitly ask the host if they had cameras, and where.
AIBU, I just can't understand how/why people do this?