Step 1: Fill the carton with less juice.
Step 2: Make the packaging smaller and say “new packaging but still as much juice as before.”

Look on the bright side: now you can make perfect 50/50 screwdrivers and not have any excess when the vodka runs out.

Been trying to cut premade/prepackaged food out of my diet lately because of health, but also because of this sorta thing. The closer the food is to its original form, the less opportunity for middlemen to come in and take an extra cut.