by blocking the ability of the sensor to sense the gaseous, it means it is reading less or minimized the reading. It will then tell the ECU to allow more air to be induce into the throttle. Theoretically, yes it is a cheap way to cheat the ECU but...
How smart / stupid your ECU is ? This is the real million dollar question....
by reducing the sensitivity of the sensor it your ECU may read it as, ah you got enough power after all, OR your car is under power.
Remember, the Sensor only responsible to read data, the ECU will be translating the data into actual action.
In short, dont cheat your sensor, tune your ECU or change one programmable ECU haha...