It's not just my opinion. A lot of people, including the police, I might add, think Batman's as unstable as the crooks he brings in.
7 seconds sound clip from the Batman: Mask of the Phantasm movie soundboard.
You can hear this line at 00:05:14.783 in the Blu-ray version of the movie.
Quote context
[...]
- Where?
- Yeah.
- I'm telling you, friends, it's vigilantism at its deadliest.
- How many times are we gonna let Batman cross the line?
- I'm sorry, councilman, but you can't blame Batman, for what happened to Chuckie Sol.
- Why not? He's a loose Cannon, Commissioner.
- What kind of city are we running when we depend upon the support of a potential madman?
- Such rot, Sir. Why, you're the very model of sanity.
- Oh, by the way, I've pressed your tights and put away your exploding gas balls.
- Might one inquire what this is?
[...]