There are three ways to not go through the full body scanner at Pearson.
1) Don't go to the USA. The machines are there because America demanded them. They are not used on non-USA flights as far as I know.
3) Don't set off the the WTMD. Usually the full body scan follows the WTMD going off.
2) Just say no. No excuse required. Opt out for a pat down. CATSA is a much nicer bunch of people than the TSA.
FWIW, I go into the USA often and do not recall going through the full body scan at YYZ but then I rarely set off the WTMD. Heck I can't even remember the last time I saw one of the units in use there.
http://www.thestar.com/news/gta/2010...ve_choice.html
To scan or not to scan?
That's the choice facing U.S.-bound passengers at Pearson International Airport as it rolls out Canada's first full-body scanner.
The high-tech scanner, which uses radio waves to peer beneath clothing to scan skin surfaces, was put into service Wednesday at Terminal One, said Mathieu Larocque, spokesman for the Canadian Air Transport Security Authority.
Passengers designated for secondary screening are offered the choice of a full-body scan or a pat-down.