Try leaving a note like this on his ladder stand:
Hey stranger! I' m so glad to see someone else will be out here hunting with me. I hunt every day of the season and it gets awfull lonely seeing as the only one I have to talk to when I' m hunting is my black lab. Anyway, I look forward to meeting you and having lengthy conversations while we hunt!
P.S. Now that I know I' ll have company I' ll bring along a couple extra summer sausage sandwiches and an extra 6 pack of Rolling Rock!
That' s good!
I would prolly handle it the same way you mentioned. Is there is a chance he/she didn' t see your ground blind? I would always be polite about it at first. If that doesn' t work, move on to other means
I would just hunt another spot opening day. Don' t let that ruin your day.