Your welcome. I'm a OTR truck driver and i think that one is sold at some truck stops. A lot of drivers are buying it themselves just for assurance, with all the new fmcsa rules and the driver rating system they have in place. And with commercial vehicles when there is a wreck it's always the trucks fault because the other person just sees money in a lawsuit against a trucking company. The first time i heard of them i think it was a news story in a trucker magazine where a car darted in front of a truck onto an exit ramp and slammed on their brakes so the truck rear ended them. Blamed the driver and said they was hurting all over. The driver just pulled his dash cam off the windshield and showed the officer what happened after the other person had given their statement. Got the driver of the car for filing a false report along with reckless driving and was talking about a fraud charge.
I would just mount them high on the windshield, keep the screen closed, and not say anything to the officer about you having one. Unless your in a state where you have to notify the other party if they are being recorded. In most states only one person in the conversation has to know about the recording to be legal.