He kept crying out that it was cutting him. The tech assured us that wasn't possible, but I insisted on checking. There were cuts on his leg--like very deep scratches.
She claimed she'd been doing this for 18 years and never cut anyone. It must have been some fluke. When she switched to the other side of the cast, she cut him again. By then, she was to the point she could insert the guard again, or I wouldn't have let her continue.
All the research I did indicated that cast saws couldn't cut skin. That is simply not true.
*edit 8-29-13: I've been told that these are actually burns because the saw became too hot. I'm not 100% sure I believe that, because it didn't look like burns. Also, he did scar.
Your poor son. Glad he's fine otherwise though.