I have had Y&R scheduled to record daily since I first got my 8300 several weeks ago. It has always skipped preempted episodes that were in the IPG, never recorded that timeslot on Sat or Sun, and has always recorded every episode that was not preempted in the IPG.
I also have The Tonight Show scheduled to record and it does the same thing, records when it's on, doesn't when it's not. However, The Tonight Show is a good example of how things can go wrong if you aren't paying attention.
If you look at The Tonight Show in the IPG, it starts at different times. It starts at 10:30 on Tuesdays and 10:35 the rest of the week. So, if you happened to schedule it using Tuesday's IPG and asked for episode in this timeslot, all you got were Tuesday's episodes and you would probably think something was wrong. If you used any other day's IPG, then you got every episode except YTuesday and also would think something was wrong. However, if you scheduled it for any timeslot, then you would get them all. Unfortunately, that would include the reruns at 2:30/2:35.
Now, you might say that is also not right because it really comes on at 10:35 every week night and you'd be right. Unfortunately, as I've said many times, the 8300 is only as good as the IPG data. If you check TitanTV, etc., you will see that it starts at 10:35 and there is something incorrect about the data being supplied by Gemstar/TV Guide.
As an added note, I don't know how Tivo would handle this and I doubt we can check because I will assume Tivo's IPG data is correct. But, even if it weren't, Tivo might handle this better because it might key on title and a New Episode flag or something like that rather than timeslot. If someone has Tivo, perhaps they can look at the IPG and see what time The Tonight Show is scheduled for each night.