you mean a relay right? in my relay it's not a requirement, but because there's no way for the client to initiate the AUTH my relay needs to send an AUTH out of the gate but if the client doesn't want to AUTH it's fine, they can keep using the relay, just with a "limited" view whereas if a relay tells you "auth-required" that's a more explicit signal that you need to AUTH to talk to it (or at least to execute that filter)
yeah that is retarded nip-11 already says auth-required i send auth i want auth no auth silence ping pong ping pong ping pong and no REQ that's what works in the real world, i've kept my client open most of the time in order to gather intelligence about how retarded the clients are and that's my conclusion unless you can forward a GTFO request upstream to your reverse proxy then just entertain them with silence