At my brother's house this year, they had 270+ trick or treaters!

We weren't there, neither was my brother & his wife - his grownup daughter (my niece) & her friend were there handing out the candy & counting the number. The hurricane put the kibosh on a lot of the neighbourhood decorations this year there, however - as everyone brought them in just before to save them blowing away. This was Maryland & they were spared the worst of the storm in the end, so the trick or treating went on as scheduled.
Their little town really organises for the trick or treating. The kids are only permitted to do it between 5-8 pm, and that's it. Local police officers patrol the whole thing & after 8 pm, any last stragglers are sent promptly home.