As someone who rides bikes too I reckon this is total bobbins. I don't even scratch my arse without doing the lifesaver check first.
Last time I checked it was "mirror, signal, manoeuvre", and you can stop at any point if it isn't safe. Signalling is just a good habit - which is why all the old buggers around me don't do it, they have crap habits from years of piss-poor driving.
Remember, signalling isn't for you, it's for everyone else, and you might have missed one despite extra checks. And personally, I generally do give a stuff about others. Seems every time I drive I get behind someone at a roundabout and I'm thinking "where the hell are you going?" because there's no indication of any sort, then suddenly they blast it all the way right, and then the best one is when they indicate after they've made the move and they're off the roundabout. Boils my piss. Same on motorways, why do people signal when they're half way through pulling in and out of lanes?