Yeah honestly this sign just screams “I don’t understand my audience”. Like, you’re selling nerdy swords to nerds in a store that seemingly caters to nerd stuff - of course the nerds interested in your products are gonna do nerdy stuff with it.
Given what the sign below it says, I think the point they’re trying to make is just that they don’t want people playing around with this stuff before buying it. I’m guessing “I’m checking the balance” or something like that is a common excuse they hear from customers who took something off the wall without permission.
The store would rather a staff member be present to minimize the risk of a customer breaking something.