Was it just SU demonstrators who were allowed to go to the convention?
 

Or did I read somewhere "guests" were allowed to go if they paid $400? Who is considered a guest if this is true?

Not sure where I read that.... or if I dreamed it up. LOL

Yes, this year, guests were able to go for $400. The only thing they couldn't do was shop at Memento Mall on the 1st day. They were able to shop there on the 2nd day tho.

A guest would be a non-demo or non-"supporting demo"
Demos and their supporting demonstrators (spouses) have always gone to Convention.

Some of the Convention deals (like the Big Shot Starter Kit discount) are not available to guests.

Guests at Convention
 

Guests were allowed this year for $400.00
Only 50 guests attended per Stampin' Up!