However, I suspect you are confusing private and public with pay and no-pay. What I saw in the developer forum did not lend me to believe there was any obstacle to going from public (or private) content for free to for pay. Please help me, then, James. How does this work?
Public and private channels are handled differently, with different sets of channels listed for each in the developer inteface. Submitting a channel as a private channel is immediate and requires no approval. Submitting for a public channel requires review and approval by Roku before it's allowed to actually go public. A public channel can never automatically be made private, nor can a private be automatically made public. It would require resubmission to the other channel queue.
When the developer is a premium developer, public channel submission process allows for payment to be required, and lets you choose the amount and interval (one time, monthly, yearly). After this information is set, it cannot be changed through the developer interface. To change the cost of a channel, the developer would have to resubmit it as a new channel in the public queue.
I stand by my strong recommendatoin Roku consider this an opt-in service. Forcing the two people I bought Roku's for (as gifts) to submit credit card information after the fact was embarassing, especially since one is too young to have a card!
I too think the better solution would be to allow a way to opt-out easily when linking the Roku, and just display a notice that there's no billing info associated with the account so it can't continue. I understand Roku's position though, which is that without a little kick in the rear, most people wouldn't bother to add a card, and wouldn't ever bother trying any premium channels. I suspect Roku is counting on store sales revenue to power their future growth, as the margins on the hardware itself can't be that much. I'm willing to forgive a little pressure from them in this are if it fuels some good advancements in the future.
There have been reports that people that really didn't want to or could not link a CC were able to bypass it by calling support, so it's not quite as bad as it sounds. There is a way to bypass it, it's just not easy, which I think is a compromise most can live with.