Tire mfg date code/sales

Some of the big tire chains will not mount or balance any tire 10 years (or more) old. Afraid of law suits (they say). I think its just a scam to sell more tires. Because not every 10 year old tire is ready to explode. Some cars sit outside 24/7/365, while others are only driven in nice weather and live in a nice garage. Obviously, the tires that are outside are going to age much faster than the pampered ones.
In November I had the tires-wheels on the 83 D150 re balanced. First think they did was check the manufacturing date on the tires. I inquired as to why they did that and I was told if the tires were more than 6 years old from the manufacture date they could not even re balance them. The tires were about 5 years old and they did do the work.