I've stayed in countless Airbnb rentals and the only time I saw a camera was in a common area shared with other guests. This was disclosed. There is no "hidden camera problem" on Airbnb. As a (legal) Superhost I place a lot of trust in my guests and have never felt the need to record them. Maybe this is because I meet at my guests in person or have a trusted friend do so. I've never felt the need to record what is go…
The thing about hidden cameras is that you can't see them. They're hidden. Unless you did a full electronics sweep on every place you stayed, that fact that you can't recall seeing one means nothing.