A very popular wiring setup with Telecasters (any guitar really) is to use a push-pull pot as a volume or tone bypass. When in use, the signal from the pickup goes directly to the output jack, bypassing the rest of the electrical components inside the guitar. The capacitors, volume and tone controls all have an impact on the signal that is generated by the pickup on its way to the output jack. This mod essentially eliminates this. The end result is the pure, unaltered true signal of the pickup.
It offers a louder, clearer and more dynamic tone (very popular with country players). Using a push-pull as a volume or tone bypass is perfect for players who tend to have their volume and tone controls always set to max. It is also used by many recording artists who strive for a consistent setting while recording and playing live. Not to mention of course, that not all players use their controls in a live situation. The idea is to have your guitar set to 10 and let the pickup do the talking.
Telecaster Wiring Diagrams