Why did PBS FRONTLINE electronically alter the signature of one of the world’s most distinguished Physicists in their report “Climate of Doubt’?

WUWT
"The signature is that of Dr. Edward Teller, from the signature card he turned in which can be seen on the very top of the Oregon Petition Project web page here. Clearly, Hockenberry was familiar with the project, citing it, and showing web pages linking to it. With that background at his disposal, there’s simply no way he could not have known that this was anybody but Dr. Teller on that card."
Heartland comments on FRONTLINE ‘Climate of Doubt’
"The quality of the program starts to deteriorate at about the 20-minute mark. Notorious global warming alarmists Gavin Schmidt, Katherine Hayhoe, Andrew Dessler, and Ralph Cicerone are presented as representative of the mainstream scientific community, which they are not. Rather than use the program to put an end to the myth of scientific consensus on this complex issue, Hockenberry repeatedly invokes the discredited myth of a 97 percent consensus. Evidence in support of that claim is farcical. The issue of what role, if any, consensus should play in science is not addressed at all."