Recently, when booking a trip, I discovered that if I included my infant when making a reservation the price was often as much as $100 more per night. When I confronted the hotel about this (we were either going to have the baby sleep with us in the King bed or bring our own travel bed), I got a load of garbage ranging from "Fire Marshal" requirements, to needing a larger room, to "I can't input it into the system". In short, it's the hotels grabbing at some extra cash as far as I can tell (though if any of you parents are in the hotel industry and care to elucidate me, I'm always eager to learn).
So, I'm looking for your own experiences: do you declare your baby when booking a hotel and take the hit, or do you just book for the couple, and try not to wave the baby in the face of the receptionist at check-in and check-out?
Note: this question is specific to infants and toddlers that don't need a third bed.