TV viewers who called a toll-free number last week to get a free T-shirt instead found themselves in trouble with the cable company. Racine TeleCable had scrambled the Sci Fi Channel signal so the only viewers who got it were those with illegal decoding equipment, system general manager Kevin Anthony said. TeleCable periodically ran a phone number across the screen for viewers to call for a free T-shirt. The test nabbed at least six cable pirates, he said.