Skilled people in general may be shy but not all .
If dowsing is a skill how can we even judge it ?
Relative abilities can be evaluated but how do you tell a good dowser from someone who is pretending to dowse “ I’ve found a processionary route over there , and there is a burial right under my feet “ .Who is to say that they are wrong or tell that they are a plant ?
I guarantee you would not be confronted . If someone tried to play even Sunday league football or sing in the local choir and were incapable they would be sussed pretty quickly .