I think the joke is nothing dangerous would be allowed within that range of a carrier during war. Sneaking a corvette within 220 nm of a carrier group just isn’t reasonable.
True. I do wonder what the current effectiveness of the new Chinese carriers? They might not have the support ships to provide an adequate zone of protection.
A submarine could get within 220nm.
A diesel-electric could get a lot closer to a Chinese carrier. More importantly, the distance between Taiwan and China is well under 220 nm so open-ocean surveillance capability isn't particularly meaningful.