I personally believe that dashcams can be very useful. I once met a Class A owner, who works for a well known Tiffin dealer. He mentioned that some time ago when driving his Class A, a lady with her kids in her vehicle, cut him off making a sudden left turn. He couldn't stop in time, and ended up rear ending her car.
The driver was uninjured and joking about incident, while the children were playing as kids often do while waiting for police to arrive. However, as soon as authorities arrived, the driver and her children began holding their necks complaining of pain. You can pretty much guess what happened next.
The driver ended up filing a suit against him. Ultimately, the judge saw through their scheme, and she was awarded $1. in damages.
Nonetheless, from then on, he has had a dashcam installed in his Class A.