Rob,
The two flag sticks are on a practice green in the new area behind the first tee on the border of Sebonack. It used to be a caddie parking lot, until they changed it a few years ago.
As for people sneaking on. I am sure it could happen around holes 8, 9, 10 etc, but the course is fairly geographically isolated and is accessible by one road. If someone tried to sneak on in the middle of winter, people would know.