This is debatable, as there was an episode or two where they could have conceivably caught others. The last episode did seem to be written with End-of-Series Awareness.
Debatable. Their scared reactions might just be because despite someone being an obvious "Scooby-Doo" Hoax, he's still a crook and might want to harm them for getting in his way, and a number of times Fred and Velma express a degree of skepticism on principle.
Took this out for being a Justifying Edit.
Removed from Genre Blindness entry for being a Justifying Edit.
Edited by MarchVee