Maybe I'm just having a big brain fart but I want to be able to put my Android phone in a state whereas it will automatically not answer calls and immediately return a text message to them. This would only be for numbers already in my contact list - a truly automatic auto-respond where I don't have to touch the phone. Now I know I could just turn it off but I'd rather have the option of being quickly able to use my phone without being bothered by others.
Probably a very simple solution that I'm just overlooking or over thinking.