Have had a couple of coaches who did that sort of thing, and these guys knew how to do it, and their teams knew what was going on.
One was a middle school level coach at one of the perennial local elite schools. Here there is no run rule at that level
, so he would always try shortening the game when possible - especially on the road. When I was new,I actually missed it, and he chastised me ..
The other was a JV coach who was around forever, and he was a master of massaging the 15 run rule. If he was playing a weak team, he'd let his girls score 5...6 runs an inning, then pull back. It seemed like if he was home, they'd be up 12-13, and then score the 2-3 he needed, and send everybody home!
A crusty old guy who never yelled at you, only at his kids - but ALWAYS had a question on a rule, that you knew he knew, but was testing you.