In my experience it is always best to remove the reg from a bottle when travelling and pack them in your hold luggage.
I have lost a bottle and regulator through customs in washington U.S.A.
They just replaced my bottle and reg. with a scrap of photocopied paper saying something about no pressurised lighters on a plane !!
If you try to take the bottle though with hand luggage some security checkpoints will not let you take it on a plane because it is heavy and could be used as a weapon !
I have also been stopped from taking a bottle with no reg on through Luton U.K. because the security woman was not sure of the rules.
As far as I know the regulations are that they are allowed in hold luggage as long as there is no regulator attached. The reason it must not be attached is twofold:
1. Security staff are not technically trained so usually can not read a pressure regulator to see it is empty so having the reg off guarantees it is not pressurised
2. They have to be able to look inside any container to check if there are any drugs or explosives in there.
I have managed to get a bottle with a reg attached back through from Turkey which had no air in but the regulator was swarf locked to the bottle.
I have heard many stories from lots of people how they have gone through customs with regs on bottles and got away with it because the customs bloke did not know what he was looking at etc. some even had pressure in them !!! But it is always best not to give them any excuse to throw away that expensive bottle and reg you just paid for !
Andy.
