Ya but don't you think she would notice a thermos?
Anyway, on mine for work I had to empty my pockets, and then piss in a cup with all these weird ass labels on it. They changed color by heat and a bunch of other stuff. I then had to sign all these forms saying I watched her close the thing, and I didn't flush the toilet or use the sink before I pissed so on and so forth.
It was a HUGE deal, kinda lame. But I was going to work for a huge corporation so I guess it's their standard operating procedure.