With a little Googling, I found a reference that US did trademark the term "Dividend Miles Multiplier" almost a year ago, so I guess it's been in the making for a while.
http://www.trademarkia.com/dividend-...-77711679.html
No doubt they're jealous of UA, who's been getting people to pay for more miles for a while. Perhaps we'll see a US version of E+ next...