In my experience, it's not unusual to find traces of mold in resale homes. As the video suggests, some of them are toxic while others pose far less of a health risk. In any case, if you notice the presence of mold in a property you're interested in buying it's definitely worth having tested. The cost of remediation can be significant if the mold is toxic and at an advanced stage.
A company like Canadian Indoor Air Quality Investigatorscan assist you with testing if you discover traces of mold in your home or in one that you're considering. They're both well equipped to remediate as well.
CMHC has also published a helpful guide titled, Fighting Mold - A Homeowners Guide that's worth checking out.
Norm Fisher
Royal LePage Vidorra