Originally Posted by mtofell

This was my first thought when reading the OP. Communication throughout hotels regularly fails so go straight to the source of the problem. I'd even take it a bit further and use some (soft surface) painter's tape and a Sharpie. Post-its are small, hard to read and can be easily removed or blow away. A piece of tape on the door with HUGE writing is hard to ignore. And I'd write it in English and Spanish.