In the 90's USA was sensible. I was flying with a thermos of hot coffee in my carry on. As soon as they took out the thermos and felt the heat radiating from the lid the agent said, "I don't think they would heat it", smiled and passed me thru.

Now when I fly I have to be careful. When they ask purpose of visit I say sightseeing. I used to say tourist, but with my accent that once caused alarm when the agent thought I said terrorist.