Do you keep your cat inside for Halloween, or is that just an old superstition?

Every year someone at the shelter reminds me to keep black cats in around Halloween, and I've never been sure if that's based on real incidents or just folklore. My indoor/outdoor tabby hates being kept in and will scream at the door all night. Do you change anything for Halloween, and has your cat actually had a bad experience with costumes, crowds or fireworks?