jumped to 5k members

I wonder, could it be related to this?

Reddit says it will review requests to make communities private or NSFW within 24 hours. For smaller or newer communities — under 5,000 members or less than 30 days old — requests will be approved automatically.

I seem to remember that when BMW first rolled out LED taillights they did something like this — they were brighter when the driver absolutely slammed on the brakes. No idea if that was a concept or in production cars though.