(I deleted the other post in the "modding and creation" section, it wasn't appropriate.)

I don't know about you, but I think seeing Sims like Bob Newbie or Tiffany Burb in Magic Town kinda immersion breaking. So I was wondering if there is a way to prevent non magical Sims (without a wand in the inventory) to appear on Magic Town lots ? If not, can a mod make it possible ? I saw several "zappers" on simlogical but none of these seem to fullfill my need.

I don't know about that. One thing to consider is that your Sim is given a magic box when they move into their home that includes a wand, spell book, and some magic coins. Surely Tiffany received the same box, along with the means to get to Magic Town. She may just be curious about the strange folks or maybe she wanted to try her hand at baking. I know for a fact that Bella Goth is addicted to the roller coaster. And who would come to see your great magic performances (I'm thinking the sleigh of hand ones) if not for your neighborhood Sims?

This is quite late, but in case anyone else has the same concern, there is a doorframe available at SomeSimThings that stops sims without a wand from entering. So you could, for example, set up a Magic Town lot where non-magical stuff like shops or mini golf is outside with an inside area that only magical sims are allowed to enter, for dueling or what have you. It's not the same as barring them from the lot entirely but it might help you maintain the illusion that there are SOME magical secrets that outsiders aren't allowed to know!

http://www.somesimthings.com/Build/02Bu.htm