And what if someone feels that everyone should be careful?
Why? If you can convince me that the Halacha is as such, then all well and good. I’ll go back and ask my Rov what should be done. But the items (e.g. the 4 inches once again, Lovesh Shechorim for women, Burkah Babes, etc.) which obviously have no Mekor whatsoever in Halacha (other than it being someone’s (Modern/Counter-Reformation) idea of a good thing), and the known and accepted Machlokesim (Separate seating on busses, Yoshan, Cholov Yisroel, etc.) there is no reason to argue one must be “careful” when there is a valid shittah that says you don’t.