For some credit cards you have no way of knowing if your friend who got PQD used points or cash. Take any CC that issues travel points that can be used after the fact to offset a charge on you statement. As far as UA knows it was a cash purchase but the person use their points to offset the cost of the ticket all within their CC vendor environment. So as far as you or UA knows they paid cash but in effect they used points and it would contribute to status. No way for UA to police this. And people using vouchers from UA to offset the price of a ticket seem to get full PQD value of the ticket (depending on type of voucher I think) so what is the difference with that? There are just too many ways a ticket can be paid for and not cost the customer actual money in the end no one could police them all.