We take our dog Trixie with us most of the time. She hasn't found any caches either but she does provide a good cover story for two people out wandering around in parks and at rest areas. Trixie always knows when we are getting ready to go . . . sseing the backpack and GPSr get her all excited for the trip.
She also enjoys sniffing, peeing and trying to roll in smeely things. Is there a dog who doesn't.