That's another point of using a smartphone for this though. It's on the Interenet while it's in your pocket. If you're somewhere remote, then it will upload while you're driving home. If they're not waiting until they get home, then they have mobile Internet access on the tablet anyway.
I'm not saying it isn't annoying. I'm just saying using online backup isn't always possible, especially on a tablet. I'm sure people using tablets do so because those screens make their images look better than they really are...except they don't realize their images aren't as good as the screen makes them look.