Personal story: Bringing liquids to airplanes is not allowed in Iran. I remember on our flight back from Shiraz, we brought about 8 liters of rose water, orange blossom water, etc. with us. The security saw it in the screen and asked what the liquid was. "Herbal water", I said. He nodded and called, "Next". Didn't even open the bottles to make sure.
Also many people bring back several liters of water from the holy Well of Zamzam[1] in their flight back from Mecca. The record I've heard of was 40 liters.