Mrs. LanikaiKid and I are in Switzerland with family but two family members need to leave in the next few days to MSP and we want to book their trips using our miles, hopefully in style. UA website shows 78.4k business availability this Friday ZRH-YUL-MSP on LX/AC but only one seat at this price. When changed to two passengers all availability is gone.

Our thought was to have separate, simultaneous UA logins and I book one of them and she books the other so they both get the deal. Other than the separate ticket issues, what other problems is there? Could LX/AC void one or both tickets? Is this just a terrible idea?