+1 for mentioning them. I have used paternosters, and I don't consider these dangerous at all. Paternosters are G.R.E.A.T fun :)

I am very aware that this type of response is anecdotal, and has a tendency to degenerate quickly into "he said, she said" style of tangents, but can we please stop calling these things "dangerous" every time they are mentioned anywhere?

I have also used old school trams that you hop on and off of, and I was a wee little kid back then and had to hop in and out, holding my father's hands. Those experience always felt more fun to me than dangerous.

Those buses are back in London:

http://en.wikipedia.org/wiki/New_Routemaster

" is notable for featuring a "hop-on hop-off" rear open platform similar to the original Routemaster bus design, but updated to meet requirements for modern buses to be fully accessible. The first bus entered service on 27 February 2012."

Never mind trams/trolleys.