Wasn't that already implicitly the case? Aren't there laws against deceptive advertising? It sounds like an incredibly sensible rule. But is this something a mayor can just declare? Isn't this something aa legislative body has to decide?
It's exactly because there are laws against deceptive advertising that Mamdani can enact theses rules.
NYC's Administrative Code prohibits deceptive trade practices, false advertising, misleading representations made to customers, etc. It gives the NYC Department of Consumer and Worker Protection authority to execute those broad guidelines by enacting specific rules.
So Mamdani and the DCWP are basically saying, "City law gives us the authority to regulate this sort of thing, and because this is clearly in violation, here are the specific rules we're enacting to regulate it."