> Frankly, the combinations of many things into unrelated fields is a design flaw.

I don't think so, not in these cases. What's the alternative? Having a different field for fusianasan, a new checkbox for sage, etc.? That's just cluttering up the interface.

> What if you want to use a name/trip and fusianasan?

Then just make one post with your name/trip and one with fusianasan and let your ID show up in both.
fusiansan is just intended for rare or special cases anyway, as is the whole subject of identification on anonymous message boards.

> What if your email address contains the string 'sage'?

Huh?

> What if you want to sage a thread, but have an ID still?

Then the board has to be configurated to just do that (it already can).

> why should I have to remember something so foreign?

It's rarely needed anyway. Also, these things are pretty easy to remember. "sage" and "fusianasan" is all there is, really.