Good that you don't trust them as ST tires just don't age as well as P or LT tires. Some are under the impression that they have to purchase tires that are in stock or locally sourced, but any reputable tire store can get any tire brand regardless of where they are located in the country, most within a few days time.
We have purchased tires from both Samsclub and Costco in the past and their service was good, but typically we use Discount Tire as they have locations everywhere making it so easy to get tire fixed or replaced same day. Keep in mind, tires store will always suggest tires with the highest profit margin first.