I let my daughter nurse at night if she wants too. She usually wakes up a couple of times to nurse for a few minutes, then she goes back to sleep.
I think people go a step too far when they say older babies are not SUPPOSED to be fed at night.
As a newborn, if she were to sleep through the night, I was SUPPOSED to wake her to nurse her every 3 hours or so, since her stomach was so small, and she needed the nourishment. It was important to feed her frequently, even at night.
At 10 months, if she were to sleep through the night, I wouldn't NEED to wake her to nurse her, since she's not really in danger at this point. She can survive through the night without a feeding, so it's not necessary for me to wake her up just to offer to feed her. However, if she lets me know she wants to nurse, I see absolutely no reason to deny her that.
Have you ever woken up with a dry mouth or throat and needed a sip of water? Can you imagine being told you need to wait until the sun comes up before you can have that sip? Babies don't have as much control over their salivary glands as we grown ups do, either, so they can't always just summon up that little bit of spit to clear their throats.