I was curious and tried it myself. I tried both "2 adults, 4 kids" (with one listed as an infant) and I tried "5 adults, 1 infant". Both of them worked. I did not get the error message about the room type being too small for the travel party. I could have booked any of the following for 5 adults and 1 infant: BCV, BWV, AKV (every booking category except the Value 1BR), OKW, VWL and SSR. ETA: I stopped at the point where it showed me the room availability. I did not select a resort and proceed to the next stage of booking. It's possible I would have gotten an error message further along in the process. However, if I put in 5 adults and a child age 3 or older, I got an error message about the room type not being able to accommodate the travel party. I suspect that is the only place the check is being done. I probably could have booked the room for 5 adults and an infant if I had continued with the reservation process.