For what it's worth, there are several municipalities that have different and conflicting rules about signalling in or with roundabouts than the provincial rule

For what it's worth, there are several municipalities that have different and conflicting rules about signalling in or with roundabouts than the provincial rules. So there is legitimate confusion about which rules to follow. At least, in Ontario. The provincial police will give you a different answer from municipal police, and I've gotten a different answer still from MoT folks. In practice, another issue I have seen is that some folks see any use of a signal near a roundabout as an indication that you are trying to "change lanes", which leads to a honk fest and more confusion immediately. So doing the "right thing" approaching or exiting a roundabout can lead to more confusion and dangerous situations than just... not signaling, unfortunately.