Amateur/Pro fights rules diff?

What do you think the rules should be regarding amateur/pro MMA fights? I know Shooto has a built in minor league system, but do the rules differ any between the new fighters and the professionals? Do you think they should differ with each other, maybe limiting certain techniques or strikes in amateur competition? Would this just be confusing to the fighters and the public? Would promoters just try to pass them off as non amateur fights?

I know some some sanctioning bodies would like to see amateur fighters wear headgear. What about fighter pay, should amateurs be paid anything? I have my own ideas on how both should be run but I'd like to hear some of your opinions on this.