I remember a new Villagers posting here who said he goes around the round-abouts saying "Please don't kill me, Please don't kill me". I think his name was Vinnie.
Nobody ever agrees on on proper procedure in the round-abouts; not everyone is on this blog and not everyone on the roads in the Villages is a Villager; so I think it boils down to be careful, give way when in doubt, and chant Vinnie's refrain.