10 yr old kid, 6-7 knot unstable wind, stalling kite, kid hooked to 18m duotone juice and teacher holding behind, what are your thoughts?
Asking the question is a bit like answering it isn't it ?
Was this done in a professional (paid) lesson?
Modern kites such as foil kites, strutless or single strut kites can fly in minimal winds even with small sizes.
However, in sub 10 knots, the only type of kite that would possibly fly AND be safe for a kid to fly would be a foil kite i.e. foil trainer kite or single skin foil kite.
I've seen many parents teaching their kids over the years and the main problems are that:
1- it's rarely done safely. Most kiters aren't good instructors.
2- it's rarely done with the right equipment. It can be difficult to find the right gear for teaching lightweight kids.
3- the level of maturity of the kid isn't good enough to handle problematic scenarios.
We cover this topic in detail in this blog post: www.kitebud.com.au/how-young-can-you-start-kitesurfing/
Christian
Yes it was a paid lesson. For me it's a no brainer, but seems like some people has other opinions.
I see, the problem here is not having the right equipment for the conditions and the student's weight or simply not having enough wind in the first place.
If it was the kid hooked up to an 18m kite on the beach in gusty low winds, chances are the kite will stall and once it goes through the power zone this can get very dangerous. Even if the instructor is holding the student, both can fly forward and the instructor can easily crush and injure the student.
However, if it was the instructor flying the kite the whole time and taking the student for a tandem body drag with a life vest on I don't see any issues.
A big kite in light wind would be safe then a small kite in strong winds for a little kid. That way there isn't big power surges as they lose control over the kite. And the kite will move slow so the kid will have longer to react.
I think
Bigger kites don't fly much better than medium sized kites in terms of light wing fly ability. There is a minimum wind speed that an inflatable kite needs just to stay in the air due to it's mass. This us usually around 6 or 7 knots. Problem is with this little wind, the kite isn't likely to turn and climb back to zenith unless its an Aluula or SLS kite, or something more specialty like a Cloud kite or similar, especially if the rider starts moving downwind with the pull of the kite which decreases the apparent wind at the kite.
Light weight kiters don't advantage by massive kites. A light weight student (35kg) will have more than enough power from a 9m light weight kite provided it will stay in the air.
A light weight ram air kite can fly in as little as 4 knots but still is only really good for beach practice unless the kite if flown by someone who really knows what they're doing.
A quality lesson shouldn't happen until a minimum of 10 knots for water practice and 8 knots for beach practice. This way, the kite will fly reliably and the student will progress.
Dodgey lesson by the sound of it. 
DM
If you want the child to develop a love for the sport then this is not a good way to start. Appropriate conditions with appropriate kite.
Can only agree with the experienced Kite instructors above that their is more appropriate smaller lightweight foil kites or single strut lightweight inflatables kites in smaller sizes that are available to instruct with.
Really irresponsible trying to teach a 10year old with a 18m Juice in marginal winds.
What about a 3m Trainer foil kite.?
The instructor should really know better.
