There's no open container law or restrictions on Aruba so feel free to take a drink to a sunny spot. You are better off taking cans to the beach as many places ban or frown on bottles. (I guess it's a safety thing.)
One of the things I love the most about Aruba is sitting outside a lovely cafe or bar with a drink. I rarely take alcohol to the beach or anywhere else outside but it's nice to know you can. I am fine with others doing it, so long as they tidy up their trash afterwards.
It still strikes me as a little strange to see people drinking openly in public, on the streets! I definitely think it's fine for Aruba as there never seems to be any trouble caused by it. Though that could be because I rarely visit the areas where the youngsters find their fun! There is nothing nicer than a simple picnic out in a park or on the beach. And no picnic is complete without a half bottle of wine!
I love sitting on the beach with a cold pina coloda from the beach bar. Even better are the beach bars that send servers around taking orders and delivering drinks. Then I don't even have to get off my lounge chair!