That would have to be clearly stated as much as they clearly state "not recommended for children under 13." But putting, "only people able to walk through the mazes are allowed" which now sounds awkward and not true since people in wheelchairs go. It's a weird balance in the terminology and something the attorneys probably can't figure out, so they just ignore it.
Also it would suck to have a baby, bring it in a stroller, get all the way to front gate and told to go home back 3 hours since they didn't read the FAQ section. It's not like wearing a costume or facepaint that they could just buy new clothes, change, or wash off in the bathroom.