I don't really care that much about a lime beer law suit here in Ontario between a large macro and a large micro. After all, these things settle out and, as Mr. Beaumont says, these sorts of beers are not exactly worth hunting out. And it's not like they are using the same name someone else thought up first. Heck, there are also lime beers from the Canadian Prairies and from the Maritimes out east. It's everywhere.
What is a little interesting to me is that these all, as I understand it, come from Miller Chill introduced in 2007 which was followed by Bud Lite Lime introduced in 2008. [Canada, you see, snaps to attention only after a modest delay of a couple of years when it comes to this sort of thing. Saves on whiplash claims.] As Lew pointed out, the whole lime beer fad was based on a Latin American trend which was to not only have a lime flavoured beer but a salty lime flavoured beer. Michael Jackson in my 1977 copy of his World Guide To Beer says that the "thirsty Mexican adds a flourish by dressing his can of beer with a slice of lemon and a little salt." But that is not what is really interesting.
What is interesting is when I was a pup in the pubs of Halifax in the '80s I would have lager and lime once in a while. Yes, I knew not what I did... I bet your youth was dandy, too. Anyway, the bartender would pour a 22 oz brimming pint glass which had a slug of Rose's Lime Cordial chucked in it. Nothing Central American about the stuff. It was a taste of Britain - or, I suppose, as certain slice of it - in a colonial port town on the North Atlantic. As Rose's has been around since 1867, a Scots' invention, and as it is tied to naval and merchant marine history... I wonder how old lager and lime really is?
The article shown above is from the May 15, 1888 issue of the West Coast Times out of Hokitika, New Zealand - a paper still in existence. Notice in the ad from 121 years ago how the lime juice is being sold as a premium drinks product along with other beers as well as spirits and wines. It sits in the list along with lager beer, separated only by one item. Who was the first to put them in the same glass?