I've only met French speakers who could switch to perfect English in Quebec province.
French speakers from France make mistakes all the time and their pronunciation is very far from perfect. (As long as I can understand them, I don't care.) That being said, someone from France's English is more than likely many times better than my French.
> In my years of experience, the most likely outcome of speaking imperfect French is just that the French person switches to speaking perfect English
If they're from Canada, maybe [1]. If they're from France, a decent chunk of Wallonie (French-speaking Belgium) or Romandie (French-speaking Switzerland), I doubt it. France has one of the lowest rates of English proficiency among the other developed countries in Western Europe and I know that first hand.
[1] And the average French person wouldn't consider what the Quebecois speak as French :p
These are two very different things. In my years of experience, the most likely outcome of speaking imperfect French is just that the French person switches to speaking perfect English.
Not saying hello+good morning is a social sanitation faux pas viewed akin to not washing your hands after using the toilet.
I'm not going to defend the latter, because it's all very formulaic, but I lived in France for years without proficiency and never had a poor encounter because of my unskilled French.