As I said before, it depends upon the community. An individual chess club can be pretty small, but the international chess federations can have a large community. Likewise, a town of 500 has a community of 500 (and perhaps the few outsiders that might go there on occasion could be considered part of the community, maybe), and a city like NYC has a huge community, numbering in the millions. And NYC can be broken down into smaller communities.
How many people in any given community have to recognize a law for it to be a law (or what you originally asked)? Well, it depends. Have you read Clayton’s posts What Law Is or A Praxeological Account of Law? If it were a community based on customary law, whenever it becomes part of the customary law or ceases to be part. If it is a statutory law community, then it’s only law if people recognize it. Where mince pies break the law… is a article by the BBC about various statutory laws that are still on the books but not enforced. These are humorous examples, but the same principle applies to existing laws today. If enough people don’t follow it, then it ceases to be law.
Well, you were the one who was using categorical statements, not me. I mean, you either agree with all laws, some laws, or no laws. Those are the only options. Once you pick one of those, I would like to read your explanation as to why you picked what you picked.