I'm not sure when it became fashionable to drink beer out of the bottle, but I have to say I don't like it. On our first trip to Mexico apart from the fact that the waiter by the pool insisted on calling me "amigo," which I thought was very forward, he compounded the sin by bringing our beers in just the bottles. I had to ask him quite firmly for "dos vasos."
Now the same thing goes for drinking it out of a can - the same gas difficulty. However there is some hope on the horizon, I think. If the canners introduce that tear off lid that is beginning to appear on all types of canned goods, then maybe with a wider neck I could do it. However until that happens, "Un vaso, por favor!"