Well the skin care wasn't liquid either.
I might do the same with the Vegemite.
One time my son began guzzling a bottle of alcohol he bought in duty-free and they called and warned the airline. He didn't drink it all, but was mad and sort of doing like you with the licking. After all, it was unopened and sold to him minutes before, receipt in hand. My daughter-in-law was mortified because she works for Delta and he was flying on a friends and family ticket and it got back to her somehow! Anyway, no rhyme or reason and I for one don't like walking without shoes where everyone else with planters warts/foot fungus has. Plus, I've seen someone go through the line with a camelback strapped to their back and walk right through. My thought was, what if that's full of chlorine, he could wipe out the whole plane? Instead, they harass a very old man about his can of Barbasol.
TSA, yay~