I have oil heat too and I struggle to imagine how you would add a sensor to it. That tank is solid and thick, trying to get anything inside it is a horrible idea and trying to sense through the metal is going to be prone to problems. In the past I’ve just pointed a camera at the main gauge.
Studies have found ( for example ) conspiracy thinking correlates with extremist political beliefs, especially right wing political beliefs, across countries. That linked study found the effect was strengthened by lack of political control.
So countries with more political extremists, especially far right wing in media platforms, leads to more popular conspiracy theories.