They could very well have enough people in Closed Beta to thoroughly stress-test the server.
The accepted limit on a single server in today's MMOG's is around 2,000. Having played most of them on a dial-up, I find that logging into a server with more that 1500 online is a waste of my time. Ping times degrade horribly and packet loss becomes a real problem.
CRS has installed, or is installing, the WWIIOL client on 25 servers. If they have 2,000 or so in closed beta, and have set that as the limit for a single server, then they are stress-testing as we speak.
They have said they have more than 500, but less than 5000, currently in closed beta.
I have some real concerns with WWIIOL. Mainly, I am concerned with a) the reduced monthly cost and it's effect on the maturity of the player base, and b) the tone of their forums.
Having said that, I will be moving lock, stock and barrel to WWIIOL when it is released. Aces High is an excellent game for fighter sim enthusiasts, and each new version makes it better for them.
For strategy-oriented players, it is a 30-dollar-a-month exercise in frustration.