A widespread law specific to the USA that doesn't seem to be a thing anywhere else in the world. We can take beers to a picnic in our parks. Shocking i know. Other societies haven't collapsed from allowing this.
This law is probably only enforced against businesses selling booze or people who are being a nuisance.
My parents were charged with this soon after coming to the US - they brought a bottle of wine to a barbecue at a public park; the bottle wasn't even kept in view, but presumably some busybody still noticed and called the police.
A jury could decide that it's a case of selective malicious prosecution and acquit the accused despite believing them to have committed the crime, but that's uncommon and a much bigger reach than a jury weighing whether the accused was engaged in disorderly conduct because they're charged with disorderly conduct.
if you are drinking from a bag, an officer must look into the bag to know you are drinking alcohol. looking into the bag requires probable cause and a 4th amendment protected search.
And when people are arrested the underfunded overworked public defenders can do a great job defending the rights of the accused.
As much as it may pain a certain someone, Canada isn't the 51st state yet.
I always thought it's strange how it would be considered very Australian to go to the beach or have a beer, but completely illegal to have a beer at the beach.