I tackle this by turning off the Novice Network chat in my chatbox. So I'm still in it but I can't see anything being said so it's like it doesn't exist. However when I log in on these alts my chat is automatically set to respond to the Novice Network despite turning off its visibility. Slightly annoying and quite redundant.

They should let players completely blacklist themselves from participating in the Novice Network, but put said option in a sub-menu so that new players won't accidentally select it during normal play while experienced players could find it themselves.