I don't see any problem as long as it is in the area that would be obscured anyway by the sun visor when that was down. There are two levels of dashcams. One simply records everything (with sound) on a continuous loop that lasts an hour or more depending on the capacity of the SD card. The more sophisticated (and more expensive) type does this and also uses GPS and real time to pinpoint the precise location and time of any 'incident'. The software is not always compatible with Apple Macs. Smartwitness is probably the most evidential.