You could add a thick layer of clear nail varnish over the lens and then have an item with little grooves over it that could be used as a stamp to place over the nail varnish whilst it dries to leave an imprint. Putting some non-stick spray onto the stamp would probably be necessary.
It may not have a hologram, but could be somewhat closer to the real thing. I doubt they can even recognise the holograms in the dark.
Any opinions on this? Or feel free to make your own suggestions and alterations.