#3 Heels and babyfaces travel separately

This one actually is a pretty old-school tradition and might no longer be relevant. However, back in the golden days when kayfabe was not as well known amongst the audience, wrestlers made sure to pretty much stick to their characters even outside the ring.
This meant that babyfaces travelled only with babyfaces, and heels with other heels, at least when they were travelling on any commercial transportation. This shows the dedication of old school wrestlers to honour kayfabe.
The best example of this is probably Nikita Koloff. Though a U.S. citizen, Nelson Scott Simpson immersed himself completely into his character of a monstrous Russian heel, by learning to speak Russian and even legally changing his name!
However, in this age of the internet, kayfabe is almost dead. The instance of Braun Strowman posting a photo standing beside Roman Reigns in the middle of their feud comes to mind. However, some old school wrestlers like The Undertaker and Kevin Owens still make sure to stay in character as much as possible. I mean, Owens made an 8-year-old kid cry for wearing a Roman Reigns t-shirt! Talk about staying in character!