It appears the Broadcast Flag, has rear its ugly head again. There have been several reports that people with Microsoft Vista, have been unable to record certain NBC programs. 
The broadcast flag allows digital signals to be either blocked completly or dimminish in quality to analog standard. The courts have ruled that FCC over step their mandate when they tried to force makers of dvr equipment or programs to implement the broadcast flag in a 2005 ruling. However the court did allow the broadcast flag to be implemented on a voluntary bases. Up to this point it has been rarely used, due to the consumer uproar. The capababilty is clearly there though, and the proof is in the above picture. Microsoft stated this was an error and was not suppose to happen, but it maybe a look into the future if broadcaster have their way. I am an avid user of Tivo, and to my knowledge no program I have wanted to record has ever been blocked. As far as the quality be downgraded, I haven't had my HD tv and hd capable TiVo long enough to know. The one thing I have noticed is that I am unable to transfer certain programs like those on BBC America from my TiVo downstairs to my TiVo upstairs. It starts to transfer, but halfway through it stops. The TV down stairs gets premimum channels, the one upstairs does not. I am unsure whether this is purely a BBC issue or if other upper tier channels are effected. It is irritating, because one of the reasons I got the secound tivo was the ability to transfer.