Cabin crew are normally forbidden from helping with carry on luggage in case of injury, or back strain from lifting a bag into an overhead locker.
Unfortunately these days liability is everything and doing something outside of your job description isn’t a good idea. What if the Captain involved had dropped a bag onto a loader’s foot and injured him ? The lawyers would have been all over it, the company would deny liability as he wasn’t trained and certified, the insurers would be singing the same tune so guess who loses his house in a damages claim ?
As for babies and children, all it takes is “He touched me.” and your career is over.
In a previous freight job, we weren’t allowed to ride in a courier van due to insurance rules, they didn’t want pilot income level claims in the event of an accident.