For various reasons, not everyone can do traditional trick-or-treating. The idea behind a trunk-or-treat is to provide a more accessible approximation of the experience. It’s also another opportunity for Halloween fun for everyone. The way it works is that volunteers, frequently business and other organizations, but also individuals, set up in a parking lot with decorated vehicles and hand out goodies to the kids who show up in their costumes. There are also typically games and other kid activities. And that’s all there is to it.