It is true that orchid nectar can be produced when bugs are muching away at the plants..but in the absence of bugs, some of my orchids WILL produce honeydew on the spikes at the base of the flowers where they attach to the inflorescence. This generally indicated a "happy" plant.
I've noticed more honeydew on some catts, phals, and ESPECIALLY cymbidiums. Some catts also produce honeydew on the new growths.
I think plants do this to draw insects to them to pollinate the flowers.