The research is a bit awkward but all the same it was done for fun, no problem. People should be allowed to enjoy their Guinness as they wish whether beaded or not. For some people their looks are worth much more than a glass of beer. Let the mustache lick some barley.
Beer drinkers should wear whatever they want. What is more remarkable about this statistic is not how many pints of beer are wasted, but how many pints of beer people who drink Guiness are drinking each year. That is the more remarkable number and the more impressive number that we should know.
If scientists are correct, and people are wasting beer by trapping it in their moustaches, than serious beer consumers should shave. If you're not a serious beer drinker, or don't care that you're losing some of your Guinness to your facial hair, than it's not a big deal is it?
Every drop of beer is precious because it takes time and effort to make it, market it and sell it. Mustaches aren't even essential to survival, there's no need for any man to grow one. As for the beer drinkers, if you love your beer, there's no need to waste it on facial hair.