I always used them too, although I sensed other passengers thought it was weird. I also wonder if the producers of on board food give any thought to minimizing chances of drips onto clothing. Prime offenders are long pieces of pasta in a colourful sauce and huge pieces of lettuce with that balsamic dressing. And those cute cherry tomatoes - they are a recipe for disaster but widely served on planes. I usually try to wear something dark, particularly on a long haul as an extra precaution.