on average, people dont like to lie. its an incentive numbers game with negligible impact to bottom line if they do it right. if budgeted like a kroger rewards card, profit accounts for every discount, even if you put in a fake phone number so theyre not tracking your spending profile associated with your collated id. moot point, no need to enforce, but the answer is passively and with shame most likely

I think you've hit on why they call it a 'pledge'