Is there a business in your town, which you are 100% sure is a front?

In the city I grew up in, there’s a Chinese restaurant near my home that never gets packed, not even on busy weekends. I’ve also never seen more than 2 customers at a time eating there. And yet, it’s outlasted every single restaurant in the vicinity for 3 decades. That, and there’s always an expensive car or two parked in front.