ERD50
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
I use a different trick. I created a ringtone that has no sound and made that the default. Then for friends and family I made another couple of unique ringtones (one for friends and a very special one for the wife). Therefore when my phone rings and I hear it I know for certain it is call I want to take. If I don't hear it it's either someone who needs to leave a message (cause they need to get a hold of me) or more likely a wrong number/robocall and I don't even bother to look at the phone.
I like that - though I'd probably make the 'silent ringtone' something low volume and subtle.
I've also been in the position where I know I could get an emergency call at night, so total silent wouldn't work. And of course, an emergency can be totally unexpected. And sometimes those emergency calls come from a cell phone not on your list.
-ERD50