Originally Posted by
looktowindward
Counter checks are legally required for IDB. VDB, is, of course, your deal with the airline. Now, United has a history of refusing to provide that legally mandated cash compensation for IDBs- they always try the flight certs and when confronted by a knowledgable passenger, they usually turn hostile.
They can get away with breaking the law. Simple as that.
Or, they simply give up, as they did with me, and find someone else that they can IDB and who does not know that they don't have to accept vouchers.