My Western viewpoint also thinks there isn't much "spec" that poorer countries follow, maybe just: if it looks like it won't collapse, it's good enough, and hopefully young people also can judge whether a building looks like it's going to collapse or not.
People in poor countries don't need scrawny wealthy college kids to help them build mud huts that are "good enough" as long as they look like they won't collapse. Not to mention that most of those kids probably have no prior experience building anything by hand or the physical strength, energy and motivation to be truly helpful.
Considering how much HN celebrates entrepreneurship and "disrupting" established business models, I wonder why you think they're more likely to be inept enough to benefit from an untrained, unskilled and likely undermotivated foreign kid helping them build things than having figured out there's a business in selling the "foreign aid" experience.
As I've replied upthread, the kids could just be told to carry bricks and wooden planks (and hammer some nails in - it's not rocket science) and they'd probably feel glad they contributed.
If I wanted to scam some Western kids, I'd just start a construction company, get them to volunteer, and tell them we're building an orphanage, while pocketing the profits for the office building being constructed. Not tell them to make something and then tear it back down when they've left.
Did you watch the NRA guy's "elephant safari" footage? Rich people in Western countries pay good money for "hunts" with their only involvement being to pull the trigger for the final shot on the already downed and dying fully domesticated animal. No need to go through he hassle of actually teaching a foreigner to read tracks and shoot straight first if they just want to feel like they accomplished something.
The point isn't to scam Western kids. The point is to provide a service. The Western kids get to "help" build something, the locals get money to actually pay for people to build it properly (or literally anything else because unlike unskilled volunteer labor, money can be exchanged for goods and services).
I'm genuinely surprised you seem to think poor countries are poor in a way that can be solved with an influx of unskilled labor. Poor countries lack money, not unskilled labor.
What's going to convince more rich Western kids to do "charity work" in your country? Using them as the untrained and unskilled labor they likely are and telling them to haul bricks for a week until they are sick of it or hurt themselves, or letting them feel like they meaningfully contribute without overexerting themselves and then clean up when they're gone so you can go back to doing something productive? Contrast the PR implications of "yeah, I went there and they only let me haul bricks for two days until I threw my back out and now I might not get the football stipend" versus "yeah, I went there and helped them build a school but I heard they had to rebuild it later". People are much more likely to glorify the later (even if they didn't contribute much) and to dramatize the former ("the food was terrible, the weather was bad, there were mosquitos everywhere, I couldn't get any sleep, I was constantly in pain and they had no doctors"). Even without getting into liability, letting the wealthy foreign kid "play" rather than do anything actually important or dangerous to them seems a far safer option.
They're selling an experience and there's a lot of money in doing that. It's just another form of tourism.
Whatever, I'll still think it's an urban legend until someone posts some credible links that says "It's true".
And it would be a lot more efficient for the locals to use the manpower properly (with supervision) rather than letting them "play" and then having to tear down what they built.
At the worst case, the helpers could just be made to carry bricks and wooden planks from 1 spot to the other, and they'd still feel that they contributed.