I think there are some good lessons here for everyone:
1) Not everyone is "in tune" with fishing/hunting etc and they think they really did good -even if the fish they caught was too small - it apparently was a big deal to them.
2) These folks could have been from IL, MN, NH, TN, FL or even WI. I have seen folks who never caught a fish in their life almost go balistic and have seen them threaten Captains here in FL when they are told the "biggest fish of their life" was way too small to keep.
3) Credit is due to the local who tried to save the fish
4) Calling the local authorities was definately the best plan, it is too bad the warden's only response is that they "have to issue citations" perhaps needed in this case, but my experience with them (and I was a police officer for 27 years) is that there is no grey area- only black and white.
5) It is difficult to judge other's motives. Obviously the renter's motives were to catch a biggest fish ever - certainly not to become wanted violators of the law. While the renter or whomever called the DNR probably did not do it to get someone in trouble, but to do the right thing and report the incident.

I would not personally lay blame on anyone involved. It was certainly an unfoturnate incident for many folks involved. I have learned long ago not to be so quick to judge, understand there are at least two (if not more) sides to every story, and perhaps most important: Learn from mistakes and understand everyone makes them.