I could see them being similar to what Amazon security uses at the gate. It would make sense to be portable so the equipment could be scanned in instead of typed.
I know of 5 loads that were either left on the yard or pulled to incorrect locations since I've been in feeders. One was a set of air going to SDFAS on a holiday weekend that a driver from another hub brought in by accident. It wasn't found during a yard audits over the weekend and was something like 6,000 pieces of late air.
I'm always amazed at meet points when other drivers hand off a set without signatures on the paperwork. Of course those are the guys who never post trip when they drop or go beyond their front landing gear before leaving. Incredibly, most are wearing patches on their shirts so I guess it has worked out OK for them.