"Goose eggs" don't typically "pop up" on tires without some sort of impact. In the past, I've ran over a street gutter by getting too close to the curb, and it left a nice softball size bump after a few days of growing. Lower profile tires are more prone to this.
FWIW, you can purchase road hazard protection including your balance & tire rotation's on your new vehicle at Discount Tire for around the price of 1 tire.
I will be purchasing Michelins next though.