While not technically I guess, the ball seems dead for all intensive porpoises when it's in the circle and runners are back on base... so seems like kind of harsh enforcement without at least a warning (especially since most umpires have let this slide from my experience).
I don't think I've ever even seen a pitcher do anything with the ball when it's in the circle and runners are back on base. If you had asked if they were even allowed to do anything other than pitch it, I'm not sure I would have been able to say yes (which I guess they technically can, though I don't know why they ever would).
Interesting thread and rules clarification, though!
I mean, you know it's not dead, so no need to get into a whole thing - but in your casual view we shouldn't care about a runner on a base just randomly jogging towards the dugout because she needs a new shoelace without calling time because, hey, the pitcher has the ball in the circle, so...
But practically speaking, in early morning dew, or drizzle games, where I know new balls are going to be constantly needed, I make a point in the plate meeting to tell the coaches to make sure their pitchers call time before tossing balls all over the place...and then inevitably in the first inning when they're just about to I preventatively call time for them, and then remind to call time. And pretty soon everyone gets it, catastrophe avoided.
Agreed that in a rec game this is ridiculously petty by the umpire.
Also, admittedly I recently had a situation where after a single, the play was stopped, the batter-runner starts jogging toward the dugout for her courtesy runner (no one called time, no one told me there was a courtesy runner), and I let it go, but with a warning - this was a single day 14u round robin.