I think it's also important to point out that young programmers often don't know that what they don't know is reasonable to not know. As one of these drywall saw guys, sometimes I'm cutting drywall because I feel like I should be able to figure out a certain amount of things on my own. When I started my first (and current) job, no one ever expressed to me that it's okay to ask lots of questions and to not know much. Sure, it's probably the junior's responsibility to ask questions, but the senior has been in both situations. The junior has been in neither. The senior engineers have to have some responsibility for letting the juniors know to ask when they're unsure of something, etc.

Also, at risk being 'that guy' (also, proud suggester of using Rails in lieu of the GWT that every developer constantly complains about), I think it would be helpful for junior engineers to pair with someone more senior, at least some of the time so that they're not halfway through cutting up the wall before it's noticed. I know I've come up with some fairly terrible solutions now that I've learned better and I'm probably doing things now that I'll look at in a couple months and think are terrible.