All the factories source all their tires such that they're M&S. And they aren't doing anything special, because almost all tires that are manufactured are M&S or better (a snowflake symbol for example).

Everybody reading this can make it a project if they like...

- next time they're in a rental car lot, try (and fail) to find a non-M&S tire
- any parking lot, try the same
- go online to, say, tirerack.com and try to find a non-M&S tire

Post back with the brand and model LOL.