I honestly hate signing the stamp. I know why it's required, but I like collecting them and to me it's sort of like defacing a work of art. I wish they had some other system where you could sign the sheet that the stamp is on, but not the actual stamp itself.
You used to be able to get a stamp from the edge of the sheet and sign the border. As long as the perforations were intact and not torn, the border was considered part of the stamp. After the season, tear off the border, with your signature, and you had an unsigned stamp. Maybe the 70's was when it changed and you had to sign across the picture, don't remember for sure.
Oh gosh, thankfully it's never happened to me. I was on a hunt a few years ago where 2 guys didn't have it signed and both got cracked. I try to ask anyone new to the group just to make sure cause we get checked 2-3 times a year.
Had a Warden check me once while duck hunting. Blue bird day, the guys in the swamp were sky busting so I heading for the parking lot. The warden .and I talked about my Lab, ducks I got that day, how the duck would be flying late that day. He check my gun, steel shot and asked about my stamp. As I was digging out my wallet I remembered I stuck it in my wallet at the post office and forgot to sign it. Told about this while getting it out and he handed me his pen. He explained that I treated right and he figured he would be busy enough after shooting hours on a sunny duck day. Just treat the Warden the way you want treated .