I think if we keep aside our smartphones and technological devices aside we can be a ghost any time. But it's difficult for us we we can't keep ourselves far from smartphone at least as we can't avoid our responsibilities for forever as you said here. By the way I was the ghost in online yesterday as I was almost inactive in online whole day.
Oh yes, I also think we can, although it can be very difficult and we won't last long without our gadgets. It's nice you had your digital detox for being offline yesterday. It's a good break, I believe :)