I spent quite a bit of time leveling up my characters, including getting a Calculator. But as Calcs have horrendous stats, the best way to do this is to use the quests at the bars. Free AP for up to three (non-special) characters!
In the midst of all my leveling, I came across two odd encounters.
A generic fight on Mandalia Plains with some throwaway Goblins and chocobos. But strangely, one was deemed a Guest and even offered to join my party afterwards...
And another odd one in Zeklaus Desert, consisting of just a bull demon and a Guest Knight. This one didn't offer to join, but he is at least 10 levels above the rest of my party at this point, so...