I used to work at a gym and I think this is something you should tell the management. It’s a huge liability on them to have an infant in the space and I can guarantee their insurance doesn’t cover it. Try to be so pissed that you mention wanting to transfer to a gym that takes their insurance rider’s seriously for their members protection. If they don’t care, ask who provides the insurance for the place and maybe they would like to know how they’re abusing the policy. You most likely will be given a month free for your membership (they should do it anyway for the heads up out of gratitude) and the woman will have her membership canceled (unless she’s friends with the owner or something ridiculous stupid that they would put friendship over a potential multi-million dollar lawsuit).