If car keys were to tap or hit my iPhone screen would it crack the screen since iPhone screens are easily cracked, and would I easily and definitely notice it if there was any cracks?
Trying to envision how the dangling keys would actually happen. You would have to be carrying your phone screen out at waist level and, in these days of social distancing, get close enough to someone who has keys dangling from their belt or hand? Doesn't seem like a common occurrence.If I was walking close to someone and they had their keys in their hand or dangling on their belt and the keys was to hit or touch my iPhone screen would it crack the screen and would I easily and definitely notice any cracks in the screen glass?
A more common occurrence is to put your phone in a pocket with keys and grit. I've done both and have never had an issue. My xs max (in an apple silicon case) also fell off a window about 4.5 up and hit a wood floor without any damage.
YMMV with all of this and make sure you have AppleCare on your phones.