There was zero wrong with that. You always have the option to buy a regular ticket if unable to non rev. You just can't do it in advance as a placeholder you only intend to use as a backup. I bought more than a few tickets commuting to work. On one occasion I had a flight attendant go crazy on me when I placed my crew bag in the overhead bin yelling something about not for jumpseaters check your bag. It was on American not my airline. I put the bag there anyway and walked straight to the cockpit and explained to the CA I was a revenue passenger and a platinum on American. I said the flight attendant yelling was unacceptable even if I had been jumpseating and if she wanted to apologize after the flight I would consider not writing up the experience to AA. She apologized but her heart was not in it. What made it better was they had a last minute no show and I got upgraded to first after her tirade!