the physics apply, but unfortunately your cornie lid seals wont. if you want to run a pressure lower than 10psi, you may need to look into a softer compound of rubber o-rings for the lid. these o-rings depend on internal pressure to keep them pressed shut and a good seal to be made, so the standard harder compound may not be up to the job.
you can by all means have a higher psi than ambient temp for short periods of time, say overnight... but i wouldn't go any longer or you'll force too much gas into the beer and end up pouring foam.
as an example, on new years eve i'd just racked some turbo cider. it was flat a witches tit with only 6 hours to go till the party. so i filled the kegs to 30psi, and left them outside in -2'c weather. when the party kicked off i let the gas down to the ambient temp under my bar and they were just starting to show enough sparkle to give the cider some lift.. was still flat, but better than totally flat. if i'd left it like that overnight it'd have been foam to the last glass :lol: