Using git pre-commit hooks to prevent bad code. Ideas?

I've warned my team that I'll be doing code reviews and checks against bad practices. I'm thinking of cooking a few git pre-commit hooks to beat them with.

Here's an example I've started building (just as a strawman)

Has anyone else tried leveraging git for code quality anywhere? I see a few examples for PHP code lint, but I want to use stronger Drupal-specific practices.

I checked out
https://drupal.org/project/githook : which drupalizes drupal git hook management, but that's not the point, I want some hook recipes to install on our repo.
Is this a BOFH idea?

#!/bin/bash
# Checks for core hacks.
# Include this in your project as .git/hooks/prepare-commit-msg

# All you have to do to allow this is to flag your commit message with the text
# "CORE HACK" in caps, and it will go through.
# If your message does not contain that string, it will be rejected.
# the --skip-verify option will also work if you are just local and lazy.

WARNING_MESSAGE="CORE HACK";

echo "Running pre-commit hook to check if you are being silly";

# $1 is the filename where the text of the message is currently held
if grep "$WARNING_MESSAGE" $1 ; then
  made_excuse=1
fi

# Check the files being committed.
git diff --cached --name-status | while read st file; do
  # Skip deleted files.
  if [ "$st" == 'D' ]; then continue; fi

  #echo "You are working on file: $file";
  bad_boy=0;
  # This list is short and rough just to spot the worst offenders.
  # Things in root dir are your own call.
  for pattern in "^includes" "^modules" "^misc" "^themes" ; do

    if [[ $file =~ $pattern ]] ; then
      echo "BAD BOY - Don't hack core."
      echo "The file change you propose to $file is in the path $pattern . I won't allow that."
      bad_boy=1;
    fi

  done

  if [ $bad_boy ] ; then
    if [ $made_excuse ] ; then
      echo "Well, OK. Just this once then"
    else
      echo "If you can figure out how to turn off this warning, then I'll trust you know what you are doing."
      echo "Until then, this commit will not go in. Hint: read about git hooks."
      exit 1
    fi
  fi

done