THE SKY IS FALLING! THE SKY IS FALLING!
WDW has continuously made an effort to keep people from going off-site, for anything. From TL & BB to Pleasure island to elaborately themed hotels to MYW, Dining Your Way, and Magic Express, and now a whole new shopping complex on the Western Beltway. And most people who go to WDW and stay on-site, if they go off-site at all, it's only a few days out of their overall vacation. Uni knows this, and they have to not only keep their "base" happy, people who enjoy Uni/IOA but clearly notice that things haven't changed all that much lately, they have to seduce WDW visitors who might otherwise never leave the Disney compound.
So offer them a deal. Make a week at Uni comparable to the price of an "add-on" option on the Disney MYW ticket, like the Water Parks Fun & More option, or a no expiration option. Potentially, it works, because what they've lost on people who would've gone to Uni anyway, is balanced out by the WDW-based visitors who are only going to Uni because of the promotion. And all those extra bodies potentially means more food, more drink, more soveneirs sold. As I said before, the WDW visitors wouldn't go offsite for more than a day or two or three max anyway, so Uni isn't really losing anything by offering the promotion to them. Aaaaand, if the rumors are true and Uni has Harry Potter & Simpsons-themed attractions in the works, what better way to spread word of mouth than by having some sort of "teaser" element in the parks, the way they teased IOA by having an information center devoted to what IOA would be. Then, not only do they have people coming this year, they'll be back when those attractions open, and they'll friends all about it.
In short, this "desperate" promotion isn't necessarily as desperate as many of you think. More people in the parks, more items sold in the parks, more word of mouth for upcoming attractions. There's only a downside if they attract people who are so blindly loyal to Disney all they're gonna do is carp about how UN-Disney like Uni is and relish loudly comparing the two when their bias is clearly evident to anyone with even half a...oh...uh...never mind.