Visibly install the labels. Not every device with a ground prong is allowed to be used in ungrounded receptacles. The stickers are required by Code to assist you at not plugging in devices they are required by NEC and devices with Instructions thethat specify they must be plugged into a grounded receptacle.
Notice that NEC 406.4(D)(2) that allows the use of ungrounded GFCI receptacles has informational notes to refer you to (UL/ETL/CSA) Listings use requirements and other sections of the NEC:
Informational Note No. 1: Some equipment or appliance manufacturers require that the branch circuit to the equipment or appliance includes an equipment grounding conductor.
Informational Note No. 2: See 250.114 for a list of a cord-and-plug-connected equipment or appliances that require an equipment grounding conductor.
Section 250.114 says:
250.114 Equipment Connected by Cord and Plug Exposed, normally non-current-carrying metal parts of cord-and-plug-connected equipment shall be connected to the equipment grounding conductor under any of the following conditions:
(3)In residential occupancies: Refrigerators, freezers, icemakers, and air conditioners Clothes-washing, clothes-drying, and dish-washing machines; ranges; kitchen waste disposers; information technology equipment; sump pumps; and electrical aquarium equipment Hand-held motor-operated tools, stationary and fixed motor-operated tools, and light industrial motor-operated tools Motor-operated appliances of the following types: hedge clippers, lawn mowers, snow blowers, and wet scrubbers.
Those labels are intended to inform you that a receptacle may not be the proper receptacle for a device you are about to use.