[Octavean]

Microsoft .wtv and .dvr-ms files are not inherently restricted. Also as already noted there are some free applications that can convert said .wtv files even at this relatively early stage. Here is another such free application / method:

Super-simple, no config commercial removal in Windows 7

This is intended for Media Center users though as it converts .wtv to dvr-ms. The problem would come in with restricted recordings and that restriction is in no small part due to how the program is flagged even with the upcoming relaxed firmware for cablecard.

It would still probably be easier to use Microsoft Media center as a front end as it can deal with its recordings and access the recordings of other applications like BTV without the need of any conversion whereas the reverse is not true.