I guess when you know that they are feeding for comfort instead of out of hunger... but even then... is it so wrong to comfort a baby in the way that they want?
I read something on another site which a mum had made her 'mantra' which I loved... she said... "If in doubt, get boobie out" LOL! Isn't it great

There is actually a link somewhere I am trying to find, it's full of information on how nightwaking is actually a very normal phyisological thing for our species.