Airlines use sophisticated technology to track unusual account activity, such as booking flights for unrelated third parties from different locations. If caught, the consequences are severe:
: Once a broker buys your miles, they typically use your account to book a "reward flight" for a third party who has paid them for a cheap ticket. The Risks of Selling we buy miles
If you have miles you cannot use, there are legitimate ways to extract value without risking your account: we buy miles