Right as always. Rain coats are for those rare occassions Paul does not hit the mark. They would not be capable of withstanding a full downpour, and certainly not hailstones, however they can extend the shoot in moderate circumstances. Generally speaking the human element gives up long before the camera would. The important thing with modern cameras, is to keep the body and mounting ring dry, as thats where the guts of the system are. lenses tend to be sealed and can take a serious pounding. Unfortunately the more expensive SLR's are the ones which can withstand the weather as they tend to be metal construction with water and wind resistance built in as part of the spec.
A good microfibre cloth for cleaning the lense and a proper chammy leather for keeping spots off the camera is a good alternative.