Super simple Selfbondag release mechanism

[dotdot]

I usually let gravity do the work, by tying a string with the key around the front or inside-tray of the drive (with a knot so it can't get loose), close the drive with only the knot and as little string as possible inside, and put the drive above me near the edge of something that I can't reach, with the key and rest of the rope on the edge in front of the drive.
When time runs out, the drive ejects, pushes the key from the edge, and if you tied your knot properly, the key will just hang there without worrying about ropes getting stuck inside or not being long enough.
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Works best with laptops and external drives, but if you have a tower, you can also remove those plastic cover-plates below a drive and make a little edge there.

It sort-of is its own backup too, since you can try to jiggle the key into dropping. So not the most secure, but better than leaving an extra key where you can get to it any time, and much better than not escaping at all.

[aldorax]

I think the CD-tray-release technique is rapidly coming to the end of its useful life given how computers are not being shipped with them anymore. :)