Isn't the rules 1 per person in line. Unless the employees waited in life off the clock, then I think it's bad form to hoard such a high demand item from the customers. What if people in line knew the store got 100, and you are number 97 and when it's your turn you find they sold out and see several employees playing with their new iphone.
Nothing could stop them I guess, and it's not as bad say when the PS3 came out and employees would try to buy them to only sell on ebay for profit, while with the iPhone, due to the contract, that's less likely why the would buy it.