Only when issuing a ticket. At least in CO there is. Therefore, each time he sends the other motorcycle cop off on his adventure to give you a ticket, first you have a right to see the device... Fighting this many tickets issued by the same cop is usually a nice adventure. Make sure you file to have them bring the device and the tuning fork for the device and records...haha! you won't get off if the don't recal the unit before every use! they go by the manufacturers spec and cal at when the next cop takes the unit to use. they may do a cehk at the end of shift, too, but there is never a requirement to recal the unit for every 'shot'!
Anyway, fight them if you get them, you will usually win.