@Havenswift Hosting - Thank you for pointing this out. Indeed, they are only checking to see if the website has any of the 65 plugins installed. 15 that they created and the 50 most popular plugins. It doesn't list or show any plugins outside of those 65.

This had me confused and I've corrected the post to more accurately reflect how the checker works. After figuring that out, now the tool is even less useful than I thought.