I've never had a point where it is dangerous. It vibrates the steering wheel and that's it. Even on the autobahn's 2.20m wide roadwork left lanes it works good/not bad enough I just leave it on. Lane keeping is not mandatory, only a warning system.
I guess it depends on the maker. For my car it nudges the wheel back into the lane in addition to vibrating.
I had lane keeping “assist” in a Subaru Forrester rental car almost kill me and my family by trying to push us into the path of a very large truck last year.