At dusk most would log off.
Because you can't see anything.
Be awesome if they added radar carrying planes. I believe the f6 had radar late in the war and a version of the P38 (P61?)
Hitech himself came in and said "most of our sibscribers logged off, so night won't be coming back" to paraphrase, during one of the many MILLIONS of reiterations of this stupid request.