The inner chrome ring corrodes from the inside and rust stains start to dribble down the vinyl .
The screws rust in too .and start to ceep rust stains too
Oh and too dissimilar metals chrome /metal screw + salt water = rust
Been there -
Ans to Q --- no the outer part does not fall off.
Back to Bulid Q issues - this weeks recurring theme . ---my next next boat ( not a SS ) has proper stainless steel frames .fixed with stainless steel screws
Sunseeker windows can end leaking .
The hole is a weak spot on the hull and any micro ( I,ll be kind and use micro -kinda excuses it ) flexing ,leads to window seal integrity falling and water ingress --rust .
If they were stainless steel and same screws used then you would not be having to remove / replace them .