R.I. Gen. Laws § 44-19-9: Advertisement as to assumption of tax by retailer.

It is unlawful for any retailer to advertise or hold out or state to the public or to any customer, directly or indirectly, that the sales or use tax or any part of the tax will be assumed or absorbed by the retailer or that it will not be added to the selling price of the property sold or upon the rental charged for living quarters in hotels, rooming houses, or tourist camps or that, if added, the tax or any part of the tax will be refunded.