On a HEL-BMA morning flight noticed a wrinkled cardboard slip, most likely tore down from some box, on the service trolley with markings in ballpoint pen:
Lumo:
Seat X
Seat Y

Plat:
Z
X
C

How lumotic is that, a real artesan handmade note!

On a full flight of 72pax, quite a lot of Lumos.