The bed is 70 pounds of broken glass, mostly window panes. Yes, I walk on it barefoot. No, I haven't cut my feet yet. No, I don't have students do it.
I followed David Wiley's advice pretty much exactly. http://www.csicop.org/si/9911/willey.html
Who knew that everytime I was doing this activity I was deriving some valuable reflexology benefits? http://www.lifeevents.org/walking-barefoot-on-broken-glass.htm