Others, like SweetWater and Lagunitas, were both using the "420" moniker (which was on Lagunitas' labels, but is in the name of SweetWater's 420 Extra Pale Ale), when things got a bit sour in the form of a cease-and-desist letter from SweetWater. Now, Lagunitas has dropped their use of the term. But with wine and beer being considered legally in the same class of products, and since there are over 3,000 breweries in America, there are fewer and fewer options for American craft brewers.
Maybe they'll just start using misspelled names instead.
Adam Lapetina is a Food/Drink staff writer for Thrillist, and wonders why nobody goes for "barley" puns. Read his musings at @adamlapetina.