Of course, dilution (from melting ice) is an adverse consequence of such a strategy.
In Birchmere v.2 (v.3 is the current venue) the beer never seemed to be quite cold enough. However, it was standard for them to bring you a glass of ice, that you would drop in the pitcher to keep the remaining beer cold, and avoid the dilution issue as well. 
They were drinking Natty Boh for god's sake. But I think the reasoning behind the 4 cubes exactly was that was the magic number of cold to dilute ratio. Old guys know some cool stuff.
