Quoted from emkay:

This is my wife's side of the family, for the most part. Getting ready to go somewhere? Finish up that beer and put a fresh one in the koozie (you do have a designated koozie, right?). Trip gonna be longer than 15 minutes? Stick a twelve pack and some ice in a cooler and put it on the back seat or pickup bed. Bad etiquette to them is reaching back for another without asking who else needs one.
One of her uncles drove the truck pulling the prize-winning float in their town fair's annual parade. He didn't want to upset anyone so he wrapped his Yuengling cans in silver duct tape and drank the entire time on the parade route with two dozen people riding on the float, waving at people while juggling a beer and the steering wheel with the other hand.
I didn't grow up like this so it certainly took some getting used to.