I wouldn't think of it as an obligation.  Those musicians didn't *have* to do that, and it the other people on the plane had expected it because "as musicians they are obligated", it might not have been as fun or cool.

I would think of obligation more as the orchestra from the Titanic playing "Nearer My God To Thee", as ordered by the captain, to try and help keep the passengers calm as the passengers that might survive were gotten into the lifeboats.  They were part of the hired crew and knew that they weren't likely to survive it, but they played.  Even "obliged", they could have refused or added their panic to the passenger's anxieties.  Instead they played.  One last show.  Doing what they could to make a terrible situation a bit more bearable, and so making a poignant moment in history.

I wouldn't say it is an obligation to "bring light and love into the souls of others", but sometimes to opportunity is there, and some may see it as a duty, others as a privilege to be able to do so. 

@StoneDog: Please don't think I'm disagreeing with the main part of your statements, but one word in there, I have a bit of a problem with.

Gift. 

If there are folks where being a musician was a gift and they never had to work for it, I guess I've never met them.  All the musicians I've known over the years put in a lot of work to learn and be able to do what they do.  If someone builds themselves a house, we don't call their house a gift.  If someone goes to college for some years to learn computer programming, we don't usually call the degree they earned a gift. 

So I've never been really clear on the popular idea that if an ability is something that is popularly considered an "art" why that automatically makes it a gift.  And not to say that building a house or computer programming do not partake of art.  They do, but some people may not see it as obviously.

If being a musician is a gift, then it would sure be nice if whoever wrapped it made it a bit less work to take out of the package.  LOL

However.. It is an asset that we can decide to make a gift of on occasion.   Much like money saved from our paychecks in a bank account that we can decide to use some of to buy a present for someone we care about or donate some of when there is some good cause like a natural disaster where we want to help the people that have been affected by it, for example.  But I see it still as something we worked to have and develop rather than something we were simply given.

There are obligations, though.  Few if any of us learned without help from others.  So it is fair to help and encourage others who are learning, since we were helped.  That's just "paying forward" and part of paying the dues.  Some of what we do so the art we enjoy and benefit from can continue and flourish.  

And it is good to use one's abilities at least sometimes to brighten the day of others or encourage or maybe even inspire others to look for ways to do something cool themselves.  It is one of the ways of making the world a better place.

But obligated?  I am not so sure of that.  If someone chooses to be a good person because it is how they follow their heart, that is awesome.  But if a person is only good because they feel they didn't have a choice, they weren't really good.  Just controlled/manipulated.

Those musicians on the plane, they were in a situation that was tedious and irritating but because they had put in some years of work to have certain abilities, they were capable of doing something to make the time more enjoyable for everyone there.  They chose to do so, and give those other folks some entertainment.  Now at *that* point, I would agree that the act of giving that performance qualifies as a gift to their fellow travellers.  But the musicians had to work to have it in the first place to be able to give it.  LOL