How can we explain. . .
Using the View button on the RCX, pointed to a port where a touch sensor is connected, it sometimes happens that the number 100 is displayed when the sensor is pressed, rather than the expected number 1. This happens when a touch sensor is connected to a port that has not been initialized to use a touch sensor, but instead was initialized to read a light sensor.
If this happens, initialize the port by running any program with a touch sensor watcher (e.g., StartTouch) block once.