I also use all 8's. I've never been asked for my real number.
A while back, my cell phone got on some telemarketer's list that went out nationwide, I believe it was Paradise Marketing. Anyway, after repeatedly asking to be removed (I am on Do Not Call List - what a joke that is), I finally resorted to recording from you tube "This number has been disconnected" Voice Message, and turned off the phone. I finally got taken off, but it took about 4 weeks of leaving it on.