Apparently people have, and apple's done nothing about it. I've found articles talking about developers thinking it's a conspiracy by apple to sabatoge web apps because then apple doesn't get the 30% cut from the App Store. :P
I found a page which mentions something that might explain it: daringfireball.net/2011/03/nitro_ios_43
That was iOS 4.3 though, so I'm not sure it applies anymore. It sounds plausible though that the extra security could be hampering nitro. Anyone know?