I never liked the machine scenarios, because tickling is an instinctive thing. Spots worsen and lighten given on mood, time of day, hell, even if you moisturized the day before. I've gone from unbearably, insanely ticklish one day to complete dead zone the next. And it takes a human understanding that, okay, her feet are no good today, let me move on. I just can't see a machine doing that.
So! I answered this poll with a human in mind. And yes, I have survived an hour. My 'ler actually tired out by that point (though props to him, because it was pretty intense) but I was on the edge of using a safe word. But tell you what, it's totally worth it.