This sign is a "Notice of Non-Responsibility," a legal document property owners post to protect themselves from mechanics' liens. If a tenant commissions work (like renovations or repairs) on a property without the owner's explicit written authorization, and then fails to pay the contractor or supplier, this notice prevents those unpaid parties from placing a lien against the property itself. Essentially, it clarifies that the owners (G.V. Povey and R.D. Murray in this case) aren't liable for debts incurred by others working on their property unless they've pre-approved the work in writing. While common in some construction contexts, seeing a permanent, vintage-looking sign like this outside a retail establishment suggests a long-term commercial lease arrangement where such a notice was deemed prudent.