+1 to everything that Eddiez said.
I suspect that most people just hang on and pray. Kids’ attention spans and depth of interest are notoriously fickle and unpredictable.
The bottom line is that a guitar is not a toy and that it does take discipline (and a lot of it ) if you ever want to get any good. You can use self discipline, or discipline imposed from without, but there’s no way around putting in the hours. Some kids need to be given 100% guidance and structure. They need it laid out and then supported, or even to some degree imposed. Others can’t hack that and will be much more self willed about it all. So there’s no “one size fits all”.
In theory, you can point them towards a nicely laid out path that’s strewn with songs and riffs that they love, and it will build slowly upwards. But in theory you could take 22 cats, split them into 2 teams and teach them how to play soccer. In theory.
The huge problem with the “Give them songs they love” idea is that it’s very hard to find things that fit the bill, and in the right order to fit their slowly growing skills. Apart from the fact that their tastes can change faster than your ability to deconstruct the latest music, there don't seem to be all that many candidates for songs that can sound even remotely right when played by a kid on one string. The Smoke on the Water riff retains its huge popularity among beginners because it is one of the very few that buck the trend, and can actually be made roughly recognisable, reasonably quickly.
Pop songs are played by a group of several professionals using thousands of dollar worth of gear, plus the enormous contribution made by a studio producer and mixer. Most simply cannot be boiled down to a small handful of single notes and still retain the feel of the original – unless you have a
dazzlingly good right hand, and a kid won’t. It's something of a downer when you find out that the stuff you
can do sounds
nothing like the original. Getting over that and moving on with the task of learning is an important part of the journey. The carnage and drop out rate at this point is horrendous!
Many tunes have survived because they are simple to sing and play, and they actually can be carried off by a single voice or instrument. You’ll still find them in many teach yourself books, laid out in order so that you can learn a few notes on one string, then add some on the next string etc. But they’re not exactly rock and roll. They’re mostly old fashioned tunes and even nursery rhymes. Not cool enough? Life’s tough kids…..
When I started out, the only way I could keep my interest up was by improvising. As soon as I could fret 3 notes I started mixing them up to see what happened. I found learning other people’s songs boring (I still do, to some extent). So why not try showing them the C major scale on one string and see what they can do with it? “Just hit any of these notes kids, and miss the others for now…”. You can also do a lot with chords on the 3 highest strings too – the E, B and G strings. Like so:
Put one finger on the high E string, fret 3. Strum the 3 thin strings – it’s a simple version of a G chord (They can strum the 4 thinnest if they like, it's still a G, but sticking to 3 strings is probably good at the start). Then try putting one finger on the first fret of the 2nd (B) string. Strum the 3 thin strings – all 3 notes of a C chord. Strum all 3 open – an E minor. G, C, Em – more than enough for a song!
"Go for it kids! I’ll be back tomorrow with a bar of chocolate for anybody who came up with a little song…."
Good luck!
Cheers,
Chris
and started playing tunes by ear. With that my parents sent me off to classes and immediatly I got the shock of my life. Having to play what I didn't want to play. I thought that the teacher and I would be jamming 
well they don't have enough symbols here anyway. 
