Recumbent bicycles

I don't know the proper name for them but there has been an increase on the bicycles that people lie back on, I went round a corner on Saturday & there were 3 in a row all hidden by the hedge and about 2 feet high, some hard braking was needed as 2 were side by side does anyone agree they should have some sort of pole with light or flag on the top so you can see them, I think it wont be long before someone has a nasty accident on one