There is a lady that was in the Tidewater Trans Am Club with me ... and shes a Va Beach Cop ... and on her T/A she had a bottle sitting right there when you look in the back window and I asked her about it ... she said its not illegal to have it ... its illegal to have any pressure showing on the guage ... but this has been almost a year ago since she told me that ... and she says it also helps if they dont see it just so they cant bitch ... so she has a cover that goes over the bottle from the back seat to the hatch ...