Originally Posted by
FreqFlyerPhil
From Wikipedia, font of all knowledge

:
"
The urinary bladder can hold approximately 17 to 18 ounces (500 to 530 ml) of urine, however the desire to micturate is usually experienced when it contains about 5 to 7 ounces (150 to 200 ml)."
Apparently, no one told my friend on the flight she had a few hundred mL to spare...

TSA only permits 3 oz or 100 ml, so either way she was a threat to our security.