When it comes to an intoxicated passenger it is not up to the pilots discretion since 14 CFR § 91.17 clearly states: Except in an emergency, no pilot of a civil aircraft may allow a person who appears to be intoxicated or who demonstrates by manner or physical indications that the individual is under the influence of drugs (except a medical patient under proper care) to be carried in that aircraft.
This pilot knowingly loaded an intoxicated passenger and had him sit in the front seat!