Usually when people see an "abandoned" nest of baby bunnies, their first instinct is to care for them, not get on google and look up what to do. You can't really blame them for trying to help, all we can hope to do is raise awareness and education!
Just a PSA in case the above wasn't clear: Mummy bunnies are only with the nest 2 times a day to nurse the babies. The rest of the time she's off feeding herself. If it's rabbit-hunting season and the babies look VERY skinny and emaciated, bring the nest to a wildlife rehabilitation centre. In all other cases, LEAVE THE BABIES. Mummy will come back. And if you are reading this thread because you took home a nest and are now googling how to take care of them - put them back right away! It's ok if you touched them, their Mum will not know the difference. Just hurry up and put them back before Mum thinks her nest is gone forever and never comes back to feed them.