I agree with the majority here: No, a teen who's participating in a family trip should have his/her necessities paid by mom and dad. Unless there are some extinuating circumstances that we're not aware of, then I think it's fair.
I would suggest that teens could be taught "the value of a dollar" by helping plan the budget. Consider it from this standpoint: Mom/Dad earn X amount per day; how many days must they work to pay for the hotel? the tickets? That may be an eye opener for the teen.
In general, I am not a big fan of teens working. "Back in the day", kids got jobs so they'd appreciate money -- it worked. Today's job market is vastly different. Take it from a teacher who hears and sees what part time jobs are really like in today's teenaged world:
First, kids are working too many hours. I think it starts out innocently enough. "Yes, mom, I will work two shifts per week -- 15 hours -- and I'll keep my grades up. Soon they realize that if they up it to four shifts per week, the paycheck is much nicer. Many parents don't step in and stop the children from working too many hours. Other parents allow the child to finance a car, and if the child doesn't work long hours, the car will be repossessed. At least 50% of my high school seniors are working 30 hours a week or more; they no longer have time to take part in school clubs, sports teams, church youth group . . . and these are activities that are only available to them for a few short years. They have years and years of work ahead of them. When will they ever again have the freedom and the opportunity to go out for the basketball team or be in the spring play?
Most of the students who work excessive hours suffer a decrease in grades (you'd be amazed how many times I look in a kids' permanant file and see that he earned As and Bs in 9th and 10th grade, then suddenly started making Cs and Ds in 11th and 12th.) Other students decide to take easier classes so they don't have to work as hard (Regular English instead of College Prep), which hurts them in the long run. Finally, there's the time away from their families. Why should we as parents allow our children to sell their childhood for a few dollars?
When we were kids, minimum wage was 3.35/hour, and our parents had the crazy idea that it was okay to butt into our lives and force us to save a portion of our wages. Today's minimum is almost twice that, and in my area kids tend to make $8-9 per hour for working fast food or retail -- that's a lot of money for unskilled labor! Additionally, I have the impression that today's parents see that money as completely the child's responsibility (despite the fact that the kids have little or no training in how to save), and the parents aren't overseeing any savings. The result: Kids have a great deal of mad money in their pockets. I regularly see kids pull out wads of twenties and even hundred dollar bills to buy school lunch (yes, they are doing it to show off, but the point is that they have it!).
Having this much disposable income sets the kids up for future problems. They develop free-spending habits as teens ($500 dresses and limos for the prom, $2000 stereo systems installed in 10-year old cars). They can do this because mom and dad are paying the bills at home, but once they move out into their own apartment, reality hits home quickly. The kid who worked 30 hours in high school, then goes to 40 hours after graduation doesn't see a significant increase in pay, but he probably moves out of the house! Suddenly he can't afford to grab breakfast at Bojangles every morning, and she can't afford to buy new outfits every week. What's the natural reaction? Disapointment! We expect life after high school to be better -- now the formerly large disposable income must go to pay the rent, and it's a bummer! It's better not to set the child up for this disapointment. It also predisposes the kid to get into credit card debt in an attempt to maintain the old disposable income.
Perhaps most importantly, I see a major attitude shift in kids once they begin working at a steady part-time job. Suddenly they THINK they are self-sufficient. They don't have the maturity and scope to realize that mom and dad are paying for the roof over their heads, the great majority of their food, etc. -- or they grossly underestimate just how much those basics actually cost. Instead, in their adolescent minds, they are on their own, taking care of themselves, responsible to no one. Often -- and I see this more often in boys than in girls -- the result is that they don't think they have to continue to be a child at home. Chores? No time -- gotta work. Curfew? I'm not a kid anymore. Liver for dinner? No way -- I'm heading to Pizza Hut; see ya later. Why set yourself up to face these battles? We see the same attitude shift at school: I'm an adult now -- who are you to say I have to be here on time? to say I can't check out of school?
As you can tell, I really don't think part-time jobs are a good thing for teens. Summer jobs -- great, in fact, I'd encourage temporary summer jobs. Babysitting or mowing lawns occasionally? That's good for kids. But a steady part-time job? Well, I've seen it backfire more often than I've seen it do good.
Let your teens be kids -- that's what they really are. They have many, many years of adulthood ahead of them. Encourage them to be young while they can -- it won't be too long before they'll have to face the real world of college, jobs, and responsibilities. And pay for their Disney tickets as long as they're in school!
I think you would also be causing a serious sibling rivalry problem by doing this! The older wondering why they are being singled out...
Last week he called home for spending money and DH had to say(gently) sorry, no, sell your X-box if you have too. You're on your own. (DS is not starving; he just wants to have his cake and eat it too.)
nly to find out,they EXPECTED it, and started slacking off. Just didn't work for us.Every family handles their finances different.Good luck 
