If anyone wonders why, it is because the UK over here has a little legal loophole where carrying acid in any reasonable (non-truckload) amount is not in any way a criminal or incriminating act, where-as guns, knives, and loads of other things are.
What is sad is it's taking so long for policians to wake up and realise that some non-scientist carrying a huge jug of acid in a backpack is kinda obviously incriminating...