I always thought it was fairly straight forward "All characters on the realm would share the Legacy name, be it as a surname, title, or member of" said Legacy. I honestly don't understand how this was confusing, not tying to be insulting at all here, I genuinely want to know. What did everyone assume would happen when they chose a Legacy name?
edit: Though I do wonder, what if you only have 1 oon on a server, choose a Legacy name then delet that toon? Does that reset it?