If you’ve got an Android phone and never want to answer calls from a specific number again, it’s easy to automatically send them to voice mail. The maneuver should come in especially handy in an election year, when phone banks and robocallers will bombard you.
A years-old, but new-to-us tip from Droid Forums walks you through the process. You open up the contact’s phone number, tap the menu key, then hit the “options” button on screen. You can then set the phone to automatically banish the call to voicemail hell without the phone even ringing.
If there are a bunch of problem numbers, you can just add them under the banner of the same contact, eliminating all of the evildoers in one fell swoop.
There doesn’t seem to be a similar way for iPhones to automatically dismiss calls from specific numbers, but when you don’t want to answer a call, double-tapping the power button atop the device will do the trick.
Found an interesting trick: Send a call to voicemail [Droid Forums]