From the DNR it appears as though it is legal for the guide (or any licensed angler) to gift their fish to another on the same day, even if that person receiving the fish has their total daily bag already that day.
Basically as long as the guide has not exceeded their total daily bag and gifted amount would not put the receiver over their possession limit, it is a legal practice, provided compensation is not explicitly exchanged for the fish.
"I have a question regarding possession limits and daily bag. NR 20.03(8)(8) states daily bag means the maximum number of fish that may be reduced to a person's possession from a specified waterbody or portion of a waterbody in one day.
If I am with a guide and catch and keep my daily limit, can I legally accept fish from the guide on the same day? I.e., I am walleye fishing and keep 5 walleye, can the guide gift me his 5 on the same day to total the 10 fish possession limit (2x daily bag)?
Hi Aaron, thanks for your questions.
Assuming a daily bag limit of 5 walleyes for the waterbody and a total daily bag limit of 5 (number of walleyes that a person can take in a single day from all waterbodies fished), another person could only gift additional fish to the angler if the person gifting the fish is still under the daily bag limit and total daily bag limit, only if the fish are gifted away from the water, bank or shore of the waterbody and only if the angler has not yet reached the possession limit of 10 for walleye (the possession limit includes all fish in the angler’s possession regardless of where the fish are being stored). Additionally, no type of compensation may be exchanged in return for the gifted fish.
Hope this helps!"