M_Boats: do I need gel cell batteries in our M17?

Hi guys, I was showing our M17 to a fellow interested in purchasing a new one and he was alarmed that the two batteries (I added a 2nd battery and a 1/2/all selector switch to be prepared for the group San Juan trip) were not gel cell type, but rather the traditional marine deep cycle trolling motor type wet cell. He said it was a big no to use that type of battery in an area where you sleep. What do you guys think? With ventilation, is the outgassing from these batteries a possible danger for us? Thanks Rick M17-635 Eidolon