I think it's just going to vary from location to location. I don't think Ballys requires the *official* Spinning certification for instructors - they might have their own type. While you probably don't need the corporate stamp to be a good teacher, it does mean that at least, you have had training in safe, effective indoor cycling methods. I like to see it when I take classes.

Last time I took a Ballys cycling class, it was taught by a guy who I swear was a retired junior high gym teacher. He wanted people to stand up the entire time, going full bore on the toughest cadence they could stand for 60 minutes. Dude yelled a bunch, had horrible (read: unsafe) form, but stopped short of calling the class a bunch of p*****s. I swear I thought that was coming. I did my own thing and never went back.