First, let's say a group of 5 hunting friends exists. As soon as one guy nails a doe...he checks it in. Then, he drives the deer to his buddy's house...removes his tag...and his buddy tags it and then checks it in. Etc, etc, etc...one guy to the next.
Thats why they slit the ear all the way up here when you register it. There were guys doing the same thing and the DNR caught on pretty quick.