The places I've hunted in IA feature some of the worst trespassing I've ever seen. Just blatant, in-your-face, no apology, ATV-driving, let the dogs loose, kid in the back of the pickup with a rifle, etc. Seriously. Sometimes every third or fourth hunt I had to deal with something like this on land that was heavily posted.
Carrying a video camera helps them find their manners usually, but my brother-in-law struggles with these arseholes. Unfortunately, he's too nice a guy. If it was me, I'd call the cops every single time.
Another thing you can count on, is that if you get permission to hunt a place that didn't allow hunting before...you will find out that place was being trespassed on, and all the locals who've been doing it will scream bloody murder that you got permission on this ground, or "leased" it, etc. When all you did was actually develop a relationship with the owner, and he let you hunt, and now you have to deal with all the idiots who have been cheating for years and their jealousy.
I find some of this to be true in my home state of NE, but especially so in western IA.