Coming from a culture where tipping is for going above and beyond the expected rather than routine... I'd treat an iPad restuarant here just the same as any other. Technically there is probably less opportunity for them to exceed expectations -v- if they'd taken the order themselves but that doesn't impact my decision.

If you want to consider wider than just the USA, you've also got to remember that in some places the service/tip goes straight to the owners and not the person that serves you (or the wider staff)