There is no reason for this role to be anything but Town-aligned. It is, however, very often X-Shot.
Use and Power
Using Sensor on the Day 1 lynch can neatly split the player list in two. If the scum are not evenly split between being on the wagon and not being on the wagon, it can become very easy to pin down who the scum are much less likely to be. Thus, Sensor is considered painfully overpowered.