Yes, and you should close the curtains, switch off the lights, sit perfectly still and not breathe! :disagree:
Seriously though, I think you and many others are way too scared about what could happen if you use the pc while burning a DVD. Modern pc's running modern operating systems are built for multi-tasking, and all DVD burners and all except ancient CD burners have buffer under-run protection that will kick in if your drive doesn't get data fast enough.
It's possible that a lot of burn stop/start cycles due to buffer under-run protection kicking in could POSSIBLY introduce more PI Errors and even PI Failures, but probably so little that you won't notice it in a quality scan unless perhaps if the stop/start cycle is happening every few seconds due to the harddrive thrashing like mad.
If you want to be on the safe side when burning, don't run anything else that massively reads or writes to the harddrive, as this is the one thing that will most likely cause buffer under-run protection to kick in.