Here is a link to a page dedicated to Ira Sherman’s latest piece – The Chaperone.
Two people are strapped into a pair of custom made harnesses. Counter weights then ¬†float them into the air, where they are brought within close proximity to each other.
If they touch however, a sensor is tripped, air pistons push the counter weights back and the people are wisked away from each other.
I helped him install this last month at the Maker’s Faire in San Mateo. I even got to ride in it.