User doesn't know or care about whose fault it is. That makes it Grooveshark's problem to fix, since Apple won't anytime soon.

If Grooveshark is advertising that it works on "all devices" then it's a Grooveshark problem.

As another commentator replied, it's something that we have to deal with. I can't speak for sure, but I think what we're running in to here is too many elements on the page. I'm sure I'm glossing over the finer details, but I'd expect whatever bugfix is made will address that.