The crowds feel like they would during a regular day, but it's night time. You know how usually when night time comes, and the crowds start diminishing. Well, it doesn't feel like that for a Coasters After Dark. It feels like 1pm crowds during the day, but it's night time. Yes, you can still have fun for a Coasters After Dark event, but if you think all the people at night are going to rush home, than you would be wrong on that for this type of night. All the flats are closed except maybe 1 or 2 (Giant Drop, King Chaos maybe are open), no shows going on, and of course the waterpark is closed. People purposely pile in the park for night time on a Coasters After Dark event. It's sort of like a privilege. I have a season pass, and this is a perk for me, so I should go. The thing is that 1/3 of attendance are season pass holders.
So, yes if you aren't thinking hey the park is going to get empty because it's night, than you should have a good time. To me, it's nothing special. One of my favorite times in the regular park is night time, and part of that reason is because people leave, and rides are emptier. I think a way that the park could make the park feel less empty during this event is to actually have all the flats running / not the water rides though. Than, the lines wouldn't be so long. And the reason they do that is to save money, and I get that. Have 15-16 rides open compared to somewhere around 30.
"I've been staring at the world, waiting. All the trouble and all the pain we're facing. Too much light to be livin' in the dark. Why waste time? We only got one life. Together we can be the CHANGE. So go and let your heart burn bright"