I've noticed it as well and it's great to see more than a handful of people in the server at any given moment, but, having frequented various other popular surf servers, I'm not sure what it is about surf servers but they just breed toxic behavior that I don't really see in other servers (like TTT or JB or ZE). I've been on a couple times when the surf server has been almost full and while it's certainly nowhere near the levels of toxic that other popular skill surf servers are, I have already noticed that without a more regular admin presence on the server, people are starting to mic spam and make racists comments and just act douchey.
I don't record demos 24/7 and can't catch everything for a player complaint but it's just something to keep in mind that as the server is more regularly populated, that this is a potential negative externality to the server being full without many admins on.
Other than that it's awesome to have a full surf server watching me break stage records :d