As it happens, HBO encoded the program with DRM--a dated self-destruct mechanism and when Tivo ran it's nightly update and the clock turned over the program was deleted without any interaction from Tivo.
(Side note: Tivo support is really good and very nice. I can't fault the company or the support team for any of this.)
I was trying to think about this a bit and figure out what HBO had to gain by removing a kids show from my Tivo without telling me and making it difficult for my baby to go to sleep. The answer is really nothing.
HBO, like all DRM obsessed companies find it necessary to "control" the content. It's especially odd in this case as HBO owns the content (meaning they wouldn't be paying royalties) and I would think they would want us locked into their service and their content.
And as far as I can tell the terms that one agrees to with HBO (or any other network) are outside the control of Tivo and Comcast, and there is no clear explanation of what might happen when, or under what circumstances when you sign up for HBO through a cable provider.
Was it wrong for me to rely on the program to be in the Tivo? I don't think so. There was no warning, or meta-data or other information that said the program would be deleted. The whole thing is just rude and an effrontery to the consumer.
Last night I ordered the DVD overnight from Amazon so that the blessed child can go to sleep. I am pretty sure that I am going to cancel my HBO subscription but I'm not sure if I am taking this too personally.
My biggest realization is that I now realize that I need to continue to own physical media as I have no idea what these scumbag companies might try to pull over on consumers.
It's pathetic that as the software world opens up, the media world continues to be an evil dark overlord.