Tech Idea: Pass codes for Phone Numbers

Haven't you ever wanted to be able to freely hand out your phone number without worrying about getting telemarketers or someone that might turn into a phone stalker and run down your minutes?

Well the phone company should support pass codes. Both a large random electronic code with contact into that people can zap between cell phones or during a phone call and simple 5 and 6 digit security codes. Then all you'd have to do is delete the security code and that person could never call you again. You'd never again have to change your number or lose contact with people because you had to change your number.

It's a simple idea and I'm surprised cell phone companies never figured it out.