So what's Halloween like at the firehouse? Pretty much the same as at home, except firefighters don't wear costumes. It could be argued that since many people like to dress up like firefighters, they're in "costume" anyway. :-)
At the stations where I worked, the crews would chip in to buy candy for the trick-or-treaters. The number of costumed visitors depended on the station's location. If there was a new guy/gal in the house, the door-answering responsibility usually fell to him/her. Otherwise we took turns, or one person who really liked that job would take it on for the night. I never minded because it was fun to see what the kids chose for costumes, and they were usually excited to come to the fire station.
Our duties didn't come to a halt, though. We still had to respond to alarms, some of which inevitably involved citizens who'd partied just a little too much.
Don't be those people. Keep your children safe, enjoy the festivities, and have a happy Halloween!