The problem is whether its DOT or HSE certified. DOT is the US safety standard and HSE is European. HSE is a stricter standard that DOT and for an european person to use a DOT certified bottle is illegal for safety reason. However if you a visiting Yank to Europe to play tornaments etc your exempt.
Lots or tourneys don't check bottles but lots do, I was playing once when a guy went for chronoing and the judge noticed his bottle was out of date, so he had change bottles.
So yep there is problems i'm afraid!!!