When we went to Disney last year, my wife carried 3 or 4 juice boxes that were about 6 oz each. She even put them in a quart size bag. My 4 year old at the time only wanted this one particular juice box so we packed some for the trip. Flying out of PIA, the TSA didn't have a problem with the juice. Coming back from MCO was a different story. I didn't hear the entire conversation but she was getting lectured about the juice boxes being too large. To carry them through, she had to get the full body patdown. They didn't go through our bags though.
As a diabetic myself, I realize I could take juice through the checkpoint. It is a good way to quickly raise blood sugar. I don't even try to bring juice because the hassle isn't worth it. Sadly, is the hassle worth it, seems to describe a lot with air travel these days.