uni-directional tires...

[T-Bird]

this is hopefully a simple question...

I was always under the impression that Uni-directional tires were only OK to use in one direction but I had some kid today trying to tell me that it was OK to use them backwards so that the water went out instead of towards the middle but I got to thinking that that would give pretty bad traction in the rain wouldn't since the flow is all messed up? also wouldn't the tires be weaker because they are designed to go in a certain direction but then someone decided to reverse them? Are there actually any consequences to running uni-directional tires backwards or not? I know in my Automotive management class we were taught that it would be against the law to allow a car out of the shop with the tires backward unless you inform the customer and they sign an agreement that they want them that way and even then you are supposed to explain it to them.