Yes, yes and yes. That's what I'm saying, and trust me it happens. Because of my weight and riding preferences I like to go out as often as possible in very strong wind, so I've probably seen more than most of these ~30kt days, and this is when it happens to me most. An example for clarity:
- I have been out kiting, come in for a break and had the kite caught for me.
- I put the bar down where I was standing when it was caught, so I know it should have been right to pick up again and go straight back out.
- Chat on the beach for five minutes.
- Go to relaunch and find a birdsnest in one or several of my lines near the wingtips where it's been fluttering.
Seriously, they tangle to the point that they will not untwist when the kite is lifted.
I find the best way to alleviate this is to keep the lines as taught as possible when it's lying on the ground, either when rigging in the first place or when it's down for the aforementioned break. The other thing, as I mentioned above, is that 90% of the time it's happened to me it's been with one particular type of line that seems to have a tendancy for it. I won't mention the brand though, they get antsy when I say things that might be bad for their profits. Plus what's the point, you should keep an eye out for it no matter what brand you fly.
Another thing is to keep your individual lines as twist free as possible. A kite line that is spiraled along its length tends to form loops on itself when not under tension, and this can lead to these sort of tangles pretty quickly. Running the length of your lines a few times before you rig up helps them untwist, as well as rolling them up neatly after a session to keep them twist free. If you've had a serious birdsnest for whatever reason (

->

) then it also pays to run the length of the lines a few extra times for this reason before using them again.