I'm not sure if this is OP's meaning, but, in that book, the moderately-wealthy live in gated communities ("burbclaves") with private security forces, who have

I'm not sure if this is OP's meaning, but, in that book, the moderately-wealthy live in gated communities ("burbclaves") with private security forces, who have nonlethal weapons that trap people in some kind of sticky expanding foam. It's just a minor world-building detail. It shows up when the initial protagonist ("Y.T.") gets involved in a scuffle while delivering pizza to one of these burbclaves. Relatedly, the pizza franchise is owned by "Uncle Enzo", a likeable Italian-American mobster. So everything is in some sense a private protection racket run by one mob or another.