An interesting way to deflect calls from certain phone numbers would be to have a machine that would automatically answer calls from that number (without causing your phone to ring) and play a recorded message. Then the machine could either hang-up or take a recorded message.
This would encourage phone solicitors and pollsters not to call phones that deflect their calls since it would tie up the callers phone lines. People could be creative in the message they played. It could be matter of fact like "Please do not call this number again" or devious like some unintelligible mumbling "muh -all -wuh.... -ently" that would keep the caller occupied for awhile saying "What? I'm sorry I didn't understand you. Could you repeat that again?"