I haven't seen it before, but I'm seeing it now.

I have no idea what UA is intending to offer, but considering not only the word "Leisure," but also that these appear specifically when I indicate, in United's software, that I'm not traveling for business, I wouldn't feel the least bit hesitant about taking advantage of these for personal travel, if I were inclined to buy a ticket at all.

Incidentally, I haven't done any widespread testing, but on the first route that I checked, the discounts under this program are substantially better, at least on deep-discount fares, than my company's corporate rate. (???) I'm seeing numbers similar to what nexus7556 reported, of approximately 10% off, even on a K fare; my company's discount for K fares is nowhere near that generous.