I feel your pain Jim. I would be torqued too.

My advice......give yourself time to cool down, then go over and talk to them in a friendly manner to explain your concerns.....leaving stuff in the field, trampling corn, possible damage to equipment, how would you feel if I drove around in your yard and ran over "your" new trees, etc. Tell them how much it could cost if you run something foreign through the combine. Their eyes roll back when they realize they may be held liable for $$thousands$$$. Best case scenario.....they were just stupid, and did not think how this affects you.

Good luck

Edit to add: I would print out the pics too and take them along, in case they want to deny any involvement.