I use QF for all my tests, and the simple solution is... just take the damn lid off when you go to poor it into the cup...

I was always told at every single test that if you had to pee more then what would fill the cup to exactly the line, to do so in the toliet... So I just pour my QF into the cup, and then piss in the toliet to make them think I really did it.

The only hard part is temp management, just make sure to check it before you pour, if it isnt the right temp, then for the love of god say you cant piss, drink some water, and wait until its warm enough.

I havent been to a place yet that wouldnt let you stay for an extra hour or two if you couldnt pee, since you fail if you leave without pissing.