my advice, get them in touch with people like shibby! or mystic (as he shoots and builds, and is kinda the guru here for that from what i glean from reading this forum), encourage them and mentor them. they don't necessarily need to start with a 22lr, but they also don't have to go out and buy a 20mm anti tank rifle.
also get them to watch the road to precision videos in the sticky on the site, blew me away and taught me quite a bit. i agree that being holier than thou is a bad idea, but also show them the video on the Remington website about the history of the m40 or m24 rifle, (i can't remember which).
there's also this program h t t p ://www.shooterready.com/lrsdemo.html, this will show them how the scopes work, and that it's not easy to make long range shots, and it's like a video game too...
I thought i'd start shooting 1000m without problems, i shoot fairly well at 200m and when i tried zeroing my rifle at 300m i learned a very important lesson, both about gear and ability. get them to make a realistic list of equipment they want/need so they have something to strive for, like rifle, glass, bipod, rings and base, stock, eis...
encourage, and mentor, as i'm sure others on this site will/could do if they're serious about it. I know when i was 15 giving me the tools to accomplish my task was make or break time, ie) i no longer skateboard, but i have 8 guitars...