My friend's Father in law!! walked into the delivery room while she was in labour! She was so upset by it and apparently it caused a few probs for a couple of months as she just didn't want to be anywhere near the ILs (as you can understand). He finally apologised to her once he realised (a couple of months later!). Its hard to imagine a FIL being that unaware of the boundaries...but I guess he was.

Chickbabe, you do exactly what you want to do and what feels right. Your friend cant wait in the waiting room if she doesn't know you've gone into labour! GL with the birth!