@JaneAir - I'm glad bi-level ventilation has been helpful for your friend, despite the inconveniences.
It sounds like it would be kind of difficult to date when you have to use one of these things! I mean, you probably couldn't spend the night elsewhere because your machine would be at your house. Also, having to explain it to someone could be a little awkward.
Then again, something like this could help a single lady weed out losers. If a guy isn't accommodating about the sleep mask, he probably wouldn't make a very good partner!