Around here, baseball just never stops, for the most part -- though some parents and coaches do seem to be wising up. But it's not really about HS based "fall ball" around here. It's about the ever growing travel industry. Our now departed former HS coach used to insist, wisely, that all of our pitchers shut it down after November 1st and not pitch for their travel teams. Several kids and parent learned the hard way that this was good advice.
But many, many travel teams here compete locally right through December. There is big tournament facility in our neck of the woods that holds tournaments right through the fall and winter, with hardly a break. They never go begging for teams to play and, in fact, almost always sell out their slots and have waiting lists of teams wanting in. The younger teams (14U and below) may take a break in mid to late December but then tey start up again just after the Xmas holidays. The HS age teams start optional, supposedly, open fields in November. That's mostly about conditioning, by section rules, to be sure, but some of the kids do their school open fields and continue to play for their travel teams.
We even have multi-sport guys on our club team who practice football all week, play a football game on Friday night, view game film on Saturday, and then come play in a baseball tournament for us on Sunday. The fear seems to be that if they are serious about baseball (and their other sport or sports) they gotta keep at the baseball even when they are in their other season. Crazy stuff. But not at all unusual in these parts. These kids seem never ever to take a rest. Don't know when it got like that. It's a bit crazy. All for dedication to craft. But a body can only take so much.