They tell that about every single safety feature in cars. Reversing cameras usually always have a warning to not rely on the image, even though basically the only way to actually get a proper view what's behind you in a modern car is to get out of the car and go behind it. I imagine it's all about liability.
Looking over your shoulder isn't part of driver's ed in the US? In Germany you'd literally fail your exam if you forget to do that even once before turning. You don't even need to move your upper body, just turn your head to the side and look in that direction and you'll cover most blind spots. They also teach you how to adjust your mirrors and how to tell they're adjusted correctly. They also do a blind spot demonstration.
Any technique you learned in driver's ed is going to be less effective on a modern car than it was on an older car because modern cars have more blind spots and expect you to use the backup camera to compensate.
I think this has less to do with "modern cars" and more to do with American preferences for SUVs. Most "modern cars" in the rest of the world haven't changed much when it comes to visibility (in fact, in some cases windscreen sizes have actually increased) but because of the trend in the US over the past decades for personal cars to get bigger and sit higher on the road, I can imagine that visibility has decreased significantly.
I'm not sure I understand you correctly though. I'm aware of "parking cameras" for driving in reverse. Are you saying American cars typically have cameras covering their blind spots that are meant to be used when switching lanes or turning? Because those are the situations for which you're supposed to do a quick blind spot check by looking over your shoulder and I can't imagine Americans who don't look over their shoulders checking cameras for those.
I just meant driving in reverse. I switched from a 1998 Nissan Maxima to a 2019 Toyota Camry. With the Nissan Maxima it was easier to look out the rear view mirror or turn around and see what was going on behind the car. With the Camry it seems that you really need to use the backup camera.
I can't find anything authoritative on this so it could be I was mistaken but it was my understanding modern cars have more blind spots in order to increase crash safety performance and the backup camera is supposed to compensate.
Here's a reddit post by someone saying they are a former automotive engineer who discusses this but obviously using a reddit post as a source is not ideal:
> They tell that about every single safety feature in cars.
> I imagine it's all about liability.
'Just ignore warnings in the manual' doesn't seem like smart strategy. Dust and snow disable those sensors frequently. Those warning are not just there for some legal reasons.
