SaltySinus said..
Yeah, it's kind of like leaving a family pet in the car with the windows rolled up...
The kite especially suffers from hot car syndrome, some brands in particular are famed for having glue with a low 'reactivation' temperature. That said, if it was my gear, and it was the only option I had to go kiting or not, I'd probably give it a crack... at least until someone smashed my window and stole my gear. Then I'd be even more bitter and twisted ...
For what it's worth, I take my kite out of my car and stick it under my desk at work... and when asked what that 'thing' is, I tell people I'm going camping. Job done.
4 kites under my desk and there wouldnt be any room for my boss