Sounds like the tyre manufacturers are just trying to cover their backsides?
Ooooohhhhhh yes. There are few parts of the auto sector that are more exposed to consumer product liability - aside from the OEMs themselves - than the tire industry.
I mean who ever sued the company who made their carburetor?
Anyhow, the tires companies make a low cost product which is definitely safety related and is widely available to every shade-tree mechanic in the world...the perfect recipe for a massive legal case. Having said that, they are innovative, yet cautious and generally do a good job in a highly competitive industry.
As a result, they are very legalistically minded and cover their products (and their @sses) with warnings, disclaimers etc.
Pete