Yes, Gold is free and you should select it. They will not interfere with your server when you do.
The major difference is that with the Gold, you can make use of their server monitoring services, be able to claim for SLA claims if the network fails and get 1 hour a month of admin time and all for free.
The Planet is about choices and there are some who may not want to enjoy the extra benefits.
Well, there were some people who actually did that but I can't remember their nick now. It was a while ago.
I believe that some misunderstood The Planet and thought that going for the managed plan would mean that Tech support woud meddle into their server so they wanted The Planet to be hand-off their server. I guess they are just paranoid enough to agree not to be entitled to SLA claims.