I don’t know how it works everywhere in the world, but in the sample size of two (2) Ikeas I’ve been to, the floor arrows are projected from overhead light bulbs with filters on them. This means that A) any decals would be obviously fake to anyone paying attention (which I understand is a depressingly high bar to clear these days), but B) anyone so inclined could just grab a chair or something to stand on – I’m sure they’re not in short supply in an Ikea of all places – and swivel the fixtures in their tracks to reorient the arrows…