I just got done reading that exact rule. That being said, it says nothing about the strap needing to be exposed. I've always understood that it can be completely cut off however I have a coach (neighbor) that is convinced that 2 inches at least needs to remain.
Since I'm the type of official that rarely goes looking for such problems I guess it's fair to say that I was not 100% certain........so I thought I would bring it to the masses for clarity.