Neither sign bothers me. I'm not the target market for that type of shop, but I appreciate the frustration.
Where I work we have very clear, big signs that say children under 14 cannot come beyond certain points. We still have kids running around the waiting area and more than once a child under 14 has been found left on their own while a parent is inside.
I would love to put up a big sign to remind people that my workplace is not a daycare, that this is a building that has suspected and convicted sexual predators in on a daily basis, and that leaving kids unattended means staff are being prevented from doing our jobs because none of us are so morally inept as to leave a child alone around suspected and confirmed sexual predators.
I would have thought this was common sense - even more than not bringing kids into a piercing studio - but it's a regular occurrence. I get sometimes people have no other options, but I've only once had a parent ask for assistance with this, because they were rightly concerned and we worked out an option for her to wait with me in the vestibule just outside the restricted area. The rest just leave their kids with a screen and hope for the best - the youngest I've had was about 6.