I assume most flight attendants, like most waiters and waitresses, have gotten the message that serving caffeinated coffee to someone who asks for decaf could be disastrous; some people react badly to caffeine, either by being unable to sleep that night (like my mom) or with a cardiac event due to high blood pressure or the like. So, you're probably not going to brew all real coffee and pretend some of it's decaf. But are you sure there isn't the potential for problems in the other direction?
The jury's not yet in on the studies that suggest the body will start metabolizing caffeine it thinks is there, whether it's there or not. But, I certainly believe it's possible that a person who drinks decaf when his body is used to caffeinated coffee may be inadvertently doing more than taking in liquid.
Sounds Pavlovian, the idea that the smell of coffee will make your body start hormonally and chemically shifting to process caffeine, but research shows there might be detrimental effects to the health if those processes kick in when there's actually no caffeine present. Until this gets clearer, I'm playing it safe by not drinking decaf, ever. Or, so I thought. Are you slipping me a mickey? Whenever I ask for coffee in the afternoon or evening, especially, or outside the coffee shop or diner context where I can be pretty confident, I always ask, "You're sure this isn't decaf, right?" Are you lying right to my face?
Would you give out all veggieburgers to passengers who thought they were getting beef? What if one of those people was allergic to soy? You probably didn't ask because it would give away your ruse, and it didn't occur to him to raise the issue because the beef he thought he was getting isn't an issue.
What if one of the people you're giving decaf to is stepping off your plane and into the pilot's seat of a private aircraft for a flight elsewhere? She thought she had caffeine before she climbed into the cockpit, but maybe not! How about the passenger stepping off your plane and into the cab of a long-haul truck that'll be hurtling down the highway overnight?
It's cute to blog about pulling the wool over the eyes of all those passengers who are now docile and easier to manage instead of hyped up, but it's not cute to actually lie about what you're serving passengers, lie about what you're giving someone to put in their body, and mess with people's metabolisms for your personal convenience. Please, please, please don't ever lie to me about what food and beverage you're handing me.