Hi John,
What happens, is the tires will wear out faster.
Radial tires DO take a set. Because radials are wound differently;
Radial tires don't grow like a bias ply tire. Air pressure and heat don't make them grow, like we used to in the old days to create stagger.
"Air pressure will change the spring rate of the tire. When air pressure is added, it stiffens the sidewall. This is the same as increasing the spring rate at that corner of the car."
Example:
"If the car is pushing at entry or middle of the turn; add 2 or 3 pounds more air to the right rear tire. This adds slightly more spring rate at that corner. Result: It will loosen the chassis slightly at entry and middle of the turn."
While it may not burst into a ball of fire, making you poular with some of the fans;
The tire will fail, maybe costing you a lot of repairs, aches, pains, and bruising.
You can swap tires front to rear. That may help you get a few more miles out of your tires.
jmho
Steve