are one of the most problematic components of a travel trailer. Some of the problems have to do with the usage pattern, which can be quite different from that of a car. I fully agree that you should pay attention to the date code when you purchase a tire. The sidewall has other information as well: load rating, where it was made, information about the structural components, max pressure rating, etc. I don't think most folks bother with any of this, which can be a big mistake. While it may seem impossible that 10 year old tires could be sold as new, no doubt it has happened to someone.
It is a good idea to record the manufacturing codes on the sales slip in case you need them for warranty purposes later on. After a blowout, that info may not be retrievable. In the case of ST tires, the warranty is usually one year after they are placed in service. Getting any kind of warranty adjustment may require quite a bit of persistence and arm twisting. That is why you should buy tires from a reputable dealer. Many dealers will give you the run around, because warranties are a bother for the dealer. Always ask about the warranty before you purchase your tires!