If you don't have any Spellcasters among the sims you play, don't go to Glimmerbrook, and especially don't go to the Realm of Magic - you will see no magic in your game.
I created a new save and played for about 5-6 Sim days staying in San Myshuno. I saw almost every Realm of Magic premade - but they didn't do anything magical. Didn't even pick up a broom.
I then went through and checked every household in household management. Only the Realm of Magic premades's were spellcasters. Vampires were more intrusive, and they were hardly intrusive. (I got a visit from Vlad and there was one Townie Vampire in addition to those from the Vampires pack)
