Smart move on their part. They need to get people thinking PVR, not TiVo. Even if they are saying PVR, if someone receives a TiVo, they will think nothing of it. But if they are expecting a TiVo and get a 'generic' PVR, there will be complaints.
Makes sense to me.
Like having a sale on 'facial tissues'. If they are Kleenex, great, but they can be JoeBob's Tissues and they aren't lying. But if they say Kleenex, it better be Kleenex.