I also chuckled at all the old golf balls here-and-there... And I heard about the swimmer -- what a miserably cold day to dive in!
Some of the balls looked to be in good condition, too! Of the first few I saw, though, the rough they were in might have deterred seekers.
One advantage of setting courses here - I will never need to BUY a golf ball again. I probably collected about 200 good balls, and on one particular trip I returned to the car with 57 stuffed in my pockets - so many that it felt like walking with weights, and I could barely begin to bend at the hips. Much of the "rough" has been cut since the course closed (they are trying to get rid of honeysuckle and other invasives, and planting natives, and doing a lot of work before this area actually opens to the public. I believe we were the first users permitted since the golf course closed, and it took a rather lengthy permitting process to get that arranged.