People do non-sanctioned leagues all the time. Since it won't be official, it won't matter if the lights are on or off. And if you have enough interested people, the center will probably support it and give you a discount on the lane usage. The trick is getting enough people interested that the center is willing to okay it. They usually will take a chance if it's a daytime league...but for prime time, I'd imagine you'd need at least 2-3 teams before they'd consider throwing it out there. And then they'd need probably 8-12 teams signed up by the start date to go forward.
The smallest league I've bowled in is the Sunday 8:00AM sport shot league...8 teams of 3. The second smallest was my first league (and only non-sanctioned) and they had like 9-10 teams of 4 and that was a Thursday evening league. In contrast, my old Friday evening league (sanctioned) folded because they only had 6 teams.
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