Murph, this may sound obvious, but are you sure they turned on the Sci Fi Channel, and not just the number channel YOU get it on? Here, I get Sci Fi on channel 48, on Cablevision. Others on Long Island, who also get Cablevision and get Sci Fi get it on a different channel number.
My brother and I used to make each other nuts telling each other to turn on this or that channel when they didn't match up!!
hope it's that simple!
rainey