On the subject of dash cams which sounds like a good idea, is is feasible easily to swap such a camera from one car to another? Reason for asking is that they appear to have the need for a power supply cable and I'm not sure how easily the cam can be connected/reconnected.
Yes they transfer easily. But a second option is to use one of those lithium battery jump start packs which can also be use to charge phones and feed things like dash cams. I haven't tried mine for this purpose yet but it would be easier than routing the wire under the dash.