Have you noticed that when you "update" a product these days, you have to be on your guard lest the vendor slip in a "downgrade"? Like when Apple "updated" iTunes to reduce the number of burns you could make from the music you bought from the iTunes Music Store?

Well, here's another reminder of how "updates" can hurt you. As reported in the PVRBlog, the latest TiVo OS "update" causes some TiVos to start popping up red copyright warning flags on certain saved programs (including the Simpsons), threatening to automatically erase programs after a certain number of days. These restrictions are part of TiVo's move, as reported last year, to lockdown and auto-erase content that is marked by broadcasters with Macrovision (a technology originally intended to befuddle analog VCRs, but now also being used as a flag to mark analog video for copy restrictions).

It looks like it was a glitch on TiVo's end this time. Only pay-per-view and "premium channel" (i.e., HBO) programs were supposed to be Macrovisioned. (In fact, section 1201(k)(2) of the Copyright Act forbids broadcasters from putting Macrovision on any other programs.)

Of course, the fact that it was a glitch this time is should be no comfort to TiVo owners. When you bought your TiVo, you could record and keep the Sopranos, or Six Feet Under, or that exclusive boxing match. Thanks to the "updates" to your TiVo, now that capability can be taken away from you at the broadcaster's whim.

It's a good reminder that, in an age when Hollywood is calling the DRM shots and technology companies acquiesce, "updates" may no longer be your friend.