I did see a very similar promo last year, that included Anaheim CA (where I was booking stays), but I can't answer your question, because I never used the promo, because I found it to be a poor value, because I calculated I would get more out of 3 "hotel hopped" separate stays without this promo than with a single 3-night stay and this promo. I think it was because it was concurrent with a stay 2 get 8000 (or similar) promo at the time, and to stay 3 nights instead of hotel hopping would cost me 8000 points, which to me are worth way more than $50.
So for the same reason I don't treat "stay 2 get a $50 GC" as "get a $50 GC" bur rather "get enough points for a $50 GC, but don't redeem for that", I didn't bite on the $50 GC for 3-night stays.
Right now, however, the "stay 2 get..." is capped, and is ending in very early May, anyway. And we don't know if there's going to be another general promo (that pays much more for hotel hopping) after that or not. So if you happen to need stays in one of these 9 cities during that time, maybe it might be the best you could do in some cases now?
Oh, and I just clicked on the link you provided, and saw that it's a Walmart GC. The value of that might be determined by how close a Walmart typically is to you. There's none around where I live, and none real convenient to where I travel most often. So actually, this is even less appealing to me than the gas card!!!
There is an Econolodge near Disneyworld that is sub-$25 a night that qualifies for this possibly. I think I saw a $21+ rate. I stayed there in Feb. Normal Econolodge. Seems to me you'd be making a profit there with this promo and the regular points.
As for multiples, I think they'd work, but better call Choice and try to get it in writing.
They ran this promo at the end of 2010 using different cities and I took advantage twice. I stay at a CS for work quite often and I don't have the luxury of hotel hopping when I'm there.
Ultimately, the rebate submission was painless; print the form, fill it out, and mail it in. However, only one rebate GC arrived and it's taken multiple contacts to get it to the point where it is now. They've confirmed that the second gift card is being processed now and I should have it in 4-6 weeks. We'll see