if both riders don't panic then they can often be flown out of each other and back to normal... If one person throws their bar in panic then it can leave the other person with two uncontrolable kites... and possibly without a functioning safety system - as the lines could be really well tangled...

Prevention is the best cure,
after that, don't panic and try to work with the other rider in flying the kites out, or landing the kites if close enough to the beach and people that can safely land them...

Ditching the kite should always be a last resort.

yea i ran into fitzies kite and our lines got crossed. Had been in hospital for a bit so i was very rusty. I had teriible tunnell vision and before i new it i had almost faded fitzy into a boat and our lines crossed We both just held the kites into positions and fitzy swam up to me and i ducked under his lines and we were away. It was a very bad situation that was really my fault. Special thanks to our local beach "mega man" for making such an issue of it. Funny how there is always some try hard hero trying to highlight their own importance through other peoples misfortune. As if i did not feel bad enough. The thing is to stay cool and keep control over your kite untill a safe solution can be organised. It seems to be very rare considering how conjested it gets out there.

It's happened to me twice, once as the chump and once as the victim.
Early last year I was on a 12m Aero II with a guy on a Vegas 12 behind and downwind on the same tack. I saw him launch for a jump out of the corner of my eye, and so I waited a few seconds before launching for a jump myself. He had an issue in the air, and came down a little sooner than expected, I went a little hiigher and farther than expected and our lines crossed while I was still in the air inducing a double kite spiral of death for about a turn and a half until my lines cut one of his, then they separated. Because I landed upside down in the water, I had trouble determining all the finer details of what happened afterwards.
Of course I apologised profusely and offered to pay for replacement lines.
Lesson learned (an oldie but a goodie) look before you leap - especially behind you, even if you think someone is long gone.
The other time was standing on a sand bar when a visiting dutchman decided to send the kite back and swing it through the window to launch into the air off the sandbank. He just didn't look behind himself before he went for it. I pulled the safety, but in retrospect, there were no downwind obstacles, so flying them out of the tangle seems less risky than pulling safeties that may jam each other with the extra spaghetti.

Yeah, lucky I was upside down and didn't see it all happening. It would have been really scary.