I'd bet people were de-burring pieces on the side of the abrasive saw before he used it.
I work in an industrial metal fabrication shop, in the last ten years I have yet to see an abrasive blade on a chop saw explode. We still keep them around, along with dry saws, cold saws and the Hydmech automated band saw.
Zip cuts tend to separate themselves from the metal ring in the centre because the operator puts too much flex on the blade. On Wednesday I had a 6" Makita grinder with a zip cut so hot I couldn't hold the body of the grinder anymore.
What scares me most is all the pictures I see on here of people running angle grinders without guards. Especially those with a wire wheel on it.
Having a bit of fear when using a tool is better then being TOO confident, thats when the bad **** happens!