Not even. LOX is explosive when it contacts organic matter like wiring harnesses, plus Dewars are very fragile, and breaking the vacuum would result in a lot of boil off.
Thanks for replying--I would have gone to my grave not even considering the fact that rocket fuel has oxidizers mixed in, but the search you just sent me on set me straight.
Before they started supercooling the LOX, it was even easier because heat transfer into LOX tanks is conventionally managed by boil-off (in launchers without supercooled propellants, latent heat keeps the liquid at a stable temperature and a trickle refills the tank continuously until a minute or two before launch).