Found in Danshui (淡水), a port city north of Taipei, Taiwan:
“禁止设摊” (Jin4 zhi3 she4 tan1) translates to “It’s forbidden to set up a vendor’s stand”
I suppose as long as you are not directly selling the items from this public space, it’s perfectly acceptable to use the space for storage or display of your vending items! The Chinese really do make use of all the space they have, interpreting signage as they wish and hanging laundry anywhere possible. Is it a result of the over-population or of just being as resourceful as possible? Probably a combination of the two.