I got tired of the roadhunting on my land years ago, so I contacted the DNR the GW has set the decoy up on my property numerous times. The very first time they did, they caught a poacher within 1hr. Sometimes they do it at night, but often during the day as well. I love it. And I guarantee you, 95% of you would think its a real deer. The only way you wouldn't is if you were there long enough that you realized it won't run. Most poachers are shooting by then. They often set it up with a doe as well, add's realism to the setup.
And yes, they do have to have permission....and they are 100% sure that where they set up is safe. They just don't randomly set up wherever they feel like. I'm glad they do it and will continue to have them set up on my property. Road hunters are scumbags.
I have also seen a decoy on the side of the road several times in other areas.