Pretty wild. It's hard to imagine that something as big and relatively close as that would have been missed by the IR satellite telescopes that have surveyed the sky. But given the options that the abstract offers for the possible distances (haven't had time to look at the whole paper), it's kind of hard to know what to think. Next thing to do would might be to have Arecibo bounce a radar signal off it. If the ALMA team's size estimate isn't wildly off, then that should be possible and that'd nail down the distance neatly. If there's no return signal, then it's got to be farther away than 25 AU, doesn't it? Given the proper motion they've identified, at least they won't likely lose track of it! It'll be interesting to see what follow-up observations are able to reveal. John