Interesting concept. I used to carry a 'nada chair'[1] in my backpack when hiking, I suspect this is much heavier though. I could totally see it as a huge win for folks who had to stand while customers were around (think the guy selling food from a cart on the street). If you motorized it so that it helped older people stand up then it could be a double win for them.

[1] http://www.gingerbreadshows.com/nadachair/