Most bats do not carry rabies, but most of the human rabies cases each year in the US are the result of contact with bats. (http://www.cdc.gov/rabies/bats/education/)

Thankfully, this is a rare occurrence with one or two confirmed cases per year.  Still, though over a ten-year period, 17 of 19 human rabies cases involved encounters with bats.  Of the 17 cases, 14 were aware of actual contact with the bats, and a handful of cases involved being awakened by a bat either biting the individual or simply landing on them from inside the home.  Others were bitten while trying to remove bats from their home.  Probably all these cases could have been avoided if the victims (or parents, in the cases involving young children) had been aware that bats can carry rabies, and sought immediate medical attention.  Not all the victims (young children sleeping) in the case study where bats were found were actually aware of being bitten.

I’d say the bottom line here is, if you awake to find a bat in your bedroom, or child’s bedroom and you don’t know if either of you have had contact, get the rabies vaccine treatment anyway.  Why take the chance?