To get back to the O.P. question:
I start and land with an anchor almost every single time I am out, no matter how many we are at a spot now.
Of course, if someone is close, they grab the kite - but only after having positioned so I can launch again from the anchor, so it really does not matter if there is someone or not (when landing).
Having done this since 2005-6 when the first SLE kites came.
With +150 sessions per year, each with numerous launch and landings, say around total 4000 times since then - this can easily get up around 2000 self launches/landings if we say that you are priviledged and have someone help you half of the time.
Out of these maybe 2000 launches, I've had 2 where the kite went up
In both of the 2 cases, I was in a hurry to get out, and havent checked lines properly.
1. Kite on its side - everything looked right - and I walked to the bar.
Kite started up quite fast, and ripped the stake up, and another kiter and I ran to the kite and no harm done.
I think that I might have had a bridle snag around the trailing edge corner of the kite, and too eager to get out so I did not notice
2. Kite on its side - everything looked right - and I walked to the bar.
Kite started rising very slowly - and with low force, but because it was close to 12 o'clock, it ripped the stake out and started drifting 75 meters before it landed on some wooden fence.
No harm done to the kite here either (but it could have been ripped to pieces, so pure luck).
I think I have had a little front line snag either at the V, or at the front bridle pulley (but most likely at the V, as I always look at the pulleys).
In case #2 it would have been easy to recover if you had a helper.
In case #1 I am happy that it was a self launch - so it was just the kite that went away, and I was not hooked into the kite
Could have been REALLY bad if you were hooked in - and sometimes even experienced helpers oversee a bridle or line snag - no matter what you say or think
I've had a few light wind launches, where the kite fell on its nose - but thats just a #¤%&" because you have to walk back (or do a slide launch), and not dangerous for you or your kite.
Two times in gusty conditions because of obstackles in front - the kite fell on its tail.
It just tumbles over one or several times then and end up LE down, downwind, and thats it.
Does not hot launch, thats for sure....
In one case there were bushes downwind, so could've been hard on the kite - but the kite was lucky again.
Regarding depower trim - it does not matter whether depowered or not, normally, and I just leave it where the trim was from last session.
Because the bar is all the way out, it is typically more important to trim the power a bit up, or FULLY up, so the kite dont fall on its nose, or flapping too much.
The SLE kites I've been using in these years, are all extremely stable when on their side
I never run my hand on the upper frontline either - it is not necessary if your lines are okay.
And in these two cases where they were not - I prefer NOT to be hooked in, so it is only the kite and not me that might be "destroyed" (erased)
I've had a bigger number of slide launches go bad (and seen many too), which is REALLY dangerous, because in case of a line snag (VERY likely on the upper side because of the kite position and you can not see anything), the kite goes up okay at first - and then continues into the power zone and you can not stop this even with bar fully pulled the other way.
Usually, when the kite hits the ground, the TE line snag dissapears (easy to see when kite dead downwind), and I can just launch the kite now.
The problem here is, that you will typically not be able to activate the QR in time - so much safer to use an anchor instead
So I think your lines or bar have been snagged somehow - and be happy that it was not you but only your kite that got hurt donohu90