Yep, that can't happen anymore... read on...

I also don't like cleats, especially on the depower system for the reasons mentioned. I love the Best bar and will most likely use it on all my kites.
On the Best bar, the stopper ball actually releases under load, the front line depower attachment under the bar works, and the pull/pull strap hasn't slipped on me once.

Yep, Donna got totally screwed one day using the cleat on the Ozone when the depower line slipped and went to full power (on the launch). She basically went from having a 8m kite in her hands to a 15m in .2 seconds and got lofted pretty good.
Even sheeting out all the way didn't help much. It was bad. Cleats and depower lines don't mix, imo.

Since that day, when using a cleat for depower, especially toward the upper end of the kite's range, I have been placing a figure eight knot between the tag end of the depower line and the cleat, to limit how far the line can "slip". In this way, you can't get TOTALLY screwed with the kite going to full power accidentally. It will only slip as far as the knot will allow.

With the SS kite, since the cleat is near the rider, you could probably adjust it on the fly in about 20 seconds. You would just remove the leash briefly, move the knot by loosening it and repositioning it, and put the leash back on.

To do this on the Ozone, I crash the kite (if the wind lightens up alot while riding) move the figure eight further away from the cleat and closer to the tag end. This allows me to power the kite more. If the wind picks up (an awful lot) I will crash it again and reposition my "safety knot" closer to the cleat to limit slip. It's a pain sometimes, but worth not getting lofted from an accidental slip. The Ozone kite has an unreal range due to the trim system, something I really like, but man, if that thing slips, it is literally like going from a 9m to a 15m kite instantly.
I tried for hours and talked to several Ozone riders on how to replace the cleat with a Pull/pull strap. Because of how the 5th line and front lines have a set 2:1 ratio to adjust trim, I couldn't figure out how to get away from the cleat.

I kind of wish the companies using the cleats would place something in line to accomplish the role of the safety knot. In sailing I think they are called clutches (little in-line cleats).
I saw some at West Marine.

Sort of off topic from the Rev, sorry. But, I think it might be worth it to get the figure eight knot or clutch idea out there.