I've never found that to be true. But there have been many issues with restoring that will cause issues so let's list them and see what you say.
1. The BIOS is not set to boot the restore media.
2. The restore media does not boot on any PC.
3. The restore media does not boot on the HP PC.
Hp help line told me that I can not restore my PC back to factory setting past a certain date. Now I called them because I already tried to restore it and now can no longer use the computer. Hp said there is nothing that can be done. The computer was bought in 2009 and recently had a new hard drive (not hp) installed. I also bought the windows vista restore disks when I put the new hard drive in and it will not let me use them. Please help. Computer is hp pavilion elite m9500f. Hard drive was installed months ago and the computers has worked with it and the windows vista install disks.