I know someone who did that, used a hairdryer on a sealed 2-pack of 2 litre bottles of lemonade. Filled one with vodka I believe, then hairdryer again to reseal. I have seen similar things on people trying to smuggle booze into cruise liners (may be an American thing - underage (20 year old!!!) drinkers).
They’ll get wise to this I am sure when everyone brings them in. Is a way round it to have several stashes of booze in the boot of your car and do several trips?