You would have thought, wouldn't you...
But I don't reckon that's how Sigelei see it. Have you seen their mechanical collection? Some of them are great with a little modification (I have two #8s, love them), some of them are [Lynn Faulds Wood]potential deathtraps[/Lynn Faulds Wood].
One of them had a switch that was basically just a split pin with a spring round it. The button just deforms the spring, connecting the two halves of the pin. I wouldn't know how to design a button properly. But I'm pretty sure it isn't like that.
Caveat emptor. Cos if we keep buying it, they'll keep making it.