I was just going to post a somewhat different question, but it was also about JFK, so I will add to this thread...

It has been a few months since I have flown on Delta from JFK, but I seem to remember that all bags (checked and carry-on) were screened before entering the terminal. Once you entered, there was no additional screening between the ticket counter and the depature gates.

So... if I have my liquid stuff in one of my bags, how will the screeners be sure that this bag will be checked?