We hesitated a long time about taking our thermos or not. It is certainly light and small, but when you travel with your house on your back, everything counts.
And then we considered the other aspect of the question, that taking the thermos meant not having to consume all those plastic or cardboard cups (without counting the money savings, enormous enough considering that we usually drink two teas a day and that one tea costs an average of 2,5 euros ...)
France, England, Norway, whether during our stay in the airports or during our flights, we only had to be polite each time (nothing more than normal), sometimes explain our approach to be entitled to a thermos filled with hot water, ready to see our tea bag lounging in there.
And then BOOM! We arrived in the USA! What to do better during our 7 hours waiting in Orlando than sleeping, playing cards and drinking tea? Well, of course, in the middle of the night, apart from McDo, there are not many places open... Matt volunteered to go there, money in his pocket just in case, and thermos in hand.
He came back a few minutes later with the thermos ... EMPTY, and a cardboard cup with a plastic lid... FULL!
"But what the hell are you doing here?" I calmly exclaimed. And Matt explained, with a disenchanted look, that the waitress had to give this cup because on it is written (in small) "Caution hot beverage" ...
He had to explain to me twice with all the patience he had left that it was a protection for them. In case you burn yourself with hot water. In our thermos. Which is made to have hot water.
Here it is ... Welcome to the USA, country of legal proceedings for a French fry fallen on the ground on which someone slips!