How do you deal with property line hunters?

My scenario: Scouting for new stand setups and making sure the property line was well marked with signs I noticed a new hang-on stand setup on the property line on the corner of a corn field. My property is the woods surrounding the cornfield. The stand is on the woods edge and positioned so it faces into the corner (the corner is corn into the woods, not woods into the corn). There is a large oak tree inside the woods and is really a pretty good choice for a stand setup. I am giving the op the benefit of the doubt that they are setup on their property, however the angle degree of area that they would be hunting on their property would be some where 90 degrees, over the cornfield. Any suggestions on how to best handle the scenario? Leave a note? I do not know the op. and I am not really interested in getting into any type of conflict as there are other areas to hunt on the property. I would just like to have the reassurance that the hunter will be respectful and not push the boundaries.

What would you do?