Truth. Although I have been knocked unconscious once and have one 10 year old elbow injury that still occasionally causes me trouble that begs otherwise, in practice. In big cities the practical rule is USUALLY the car will turn if it thinks you can reasonably stop in time, and occasionally they'll turn whether or not they think you'll stop in time. A couple times a year the car will just smash you to turn, because fuck cyclists they shouldn't have been on the road.

I would never advise cyclists to consider what you've stated as the actual rules. In practice the rule you should follow is the person turning will turn if they reasonably believe you have time to stop, and prey they do not alter the deal further. De facto vs De jure.