What are the 5V and VIN pins for?
No. You can draw power from the 5v and VIN pins on the arduino. VIN is the completely unaltered input power before the regulator (it will be useless if regulated 5v is supplied directly). Outputting power is what the 5v pin is intended to be used for, not as a power input.

From the arduino website:


  5V. This pin outputs a regulated 5V from the regulator on the
  board. The board can be supplied with power either from the DC power
  jack (7 - 12V), the USB connector (5V), or the VIN pin of the board
  (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the
  regulator, and can damage your board. We don't advise it.