One-Stop-Shop
There are two ways to look at this, one is a fun way, and the other is the ‘yuck!’ way. Few airlines provide you with only one personal item to keep your stuff when on the journey before you are required to pay a wholesome amount for another bag. Maybe this person was in an attempt to be careful and save some money.
till, would you put a dirty diaper with the drinks you brought to keep you hydrated? That doesn’t sound appealing even to the slightest bit, rather more towards the filthy side.