The coupon National e-mails you says it can not be sold, bartered, etc. It sounds like they could match the unique code to a person's Emerald Club account. If they catch you, they could theoretically make you pay the full walk-up rate and/or put you on the Do Not Rent List. Maybe someone with a lot of 1-2 Free days to spare should e-mail National to ask about giving them to family or friends, and post the answer here.