That was a long time ago when niggas used to put their cans in a backpack. These days the cops roll up on you if you're even out at night with a backpack on and sometimes even if you have a grocery bag that don't look right. I'm pretty sure the kid's talking about for grocery bags so the outline just looks like a regular 6 pack and so the cans don't make alot of noise as you're walking down the street or climbing shit. I think it's kind of a good idea although I seriously doubt that I'd ever go through the trouble of gathering all these pringles cans.
And if you were walking around with a milk crate full of cans, chances are the only walking you were doing was from your car to the wooded trail that led to some train tracks where you didn't have to worry about anybody seeing you walking around with a milk crate full of paint.