When we were at Surfwatch in March we were not even given wrist bands. I don't recall seeing them on anybody. When we went to Ocean Watch last April we did have wrist bands given to us on check in and were asked to show them on several occasions. It was at full capacity as it was over Easter week end.
At SurfWatch they use them throughout the entire Platinum (summer) and only partial Gold (late spring/early fall) seasons, and during holiday weeks. They're not the hospital band-like ones shown in the picture for Ocean Pointe but the silicone ones that can be easily removed. You don't have to be wearing them but Security definitely checks to be sure that everyone at the pools and other common areas has one. (Mine is usually in my bag.)
The only exception I know of is at the bar/grille near the ocean - like the other HHI properties people can come off the beach and use cash to get a bite to eat or something to drink, but they have to either take it back to the beach or sit in the areas designated for eating nearby. So if a food activity is scheduled, like the crab legs/shrimp buckets or brauts/beer tastings, Security will be there looking for the bracelets.