One of my maid is also like that - cause she has no friend and no where to go - and also no money to go. then she could take lunch at home then go out for few hours.
Sometimes she is really tired and want to sleep but if she goes out there is nowhere for her to sleep.
But make sure she sign the record for acknowledging the leave otherwise afraid that she claim she has not taken the leave at all. And make sure you don't ask her to do anything during the holiday time. Better to have someone as witness also.