I think the first time I saw releasable zip ties was in one of Doug Ritter's kits. I've looked for them in stores ever since, but have yet to see them.

I figured if shelter building or making repairs weren't going well and things were going south (mental strain, physical injury), then having releasable zip ties might provide a second/third... chance to get it right.

Of course the release feature isn't so good if you're using them as little tiny handcuffs.