muppet:wasabi2k:
Why would you need to enforce a pin or lower transaction value?
In answer to this, I ask my own question to you: Why do they require PIN above $80?
It's all about risk - the first thing people (traditionally) have tended to do with a stolen card is buy high value items. They don't go around buying low value goods.
I remember in my supermarket days that it was just about guaranteed that stolen cards would involve the purchase of multiple packs of nappies, cigarettes and expensive steak.