Be wary of handing the kit to someone who has no idea what they are doing, unless you are going to supervise them.
These are not the kites of childhood where you need a gale and to run like the clappers to get them to fly ;o)
Kites are not a blunt instrument but a delicate scientific tool.
(Having said that, when Jim and I were out with the Edinburgh University Archaeological Society, in Edinburgh last week, we flew in very strong winds. Jim used a higher wind speed Dan Leigh, Trouper Delta and the students and I flew their Power Sled 24. I also flew the near indestructible HQ FF 2.0, but was almost pulled over!!)
As you say John you have to be careful when handling sparred kites especially in gusty wind conditions. If it's a bit breezy the spars tend to be at greater risk when handling the kite pre launch. Once you get some height things tend to settle down but care has to be taken with upper wind limits.
Yes, safety first on this one please. If the wind looks and feels too gusty, the poor old delta's spars may not be up to the job. There are specialist kites that we fly, but they are in the hands of seasoned flyers who have the correct set-up to manage these higher winds. We always find flying the spar less kites such as the power sleds and flow forms fly much better with a good wind behind them.
If the kite is in the sky and you can see that the spars are really bending back, then the kite is probably not suitable for these conditions. Try another kite or come back another day for more calmer conditions and less stress.