Does anything bad happen if you stay up too late too much? Master Urwald scolds you, but that's not a big deal. It doesn't even say "Master Urwald did not like that." Does anything bad happen if you stay up late every day?

Your mental stats will suffer a bit for being tired. It isn't a huge difference, but it might be worth taking a nap if you're about to try something that needs a high value in one of them.

You need to suffer through a lot of snide remarks from Master von Urwald. :-)

Shawn's schedule is largely informed by Lori's and mine, except that if we're in bed by 1 a.m. it's a minor miracle. There are some "short on sleep penalties," but no long-term bad effects. As Garran mentioned, you can always have Shawn return to his room and nap for an hour to remove the debuffs. Or just work through them.