Not U at all - sounds like a colossal cheek to ask.
I long ago stopped 'sponsoring' these expensive trips where inexperienced, unskilled teens go to 'help' build schools or whatever, in 3rd world countries.
What on earth they can do that couldn't almost certainly be done better, and a lot more cheaply, by the same organisation paying local labour to do it - local labour that might well be very glad of the opportunity to earn some money - I can't imagine.
I can see that it opens 1st world - and often privileged - young people's eyes to the realities of life in poor countries, but the same could be achieved by an organised visit, without the somwhat pious facade of 'good works' that need to be sponsored.
If it were expected that the young people should earn the cost of the trip themselves, that might be different, but all I've ever known is virtual begging for friends or relatives to cough up for their 'jolly'.