I've had my "most used" Swisstool develop a bit of rust also (through my own fault
), after I cleaned him in a bit of soapy water I put him in a plastic box with clean water (no soap) and forgot I put it in there, when I found out that I've left him in the water two days later the "lock-release buttons" where rust coloured. A bit of metal polish and all the rust was gone, but it was still a bit of a surprise when I saw the brown/red buttons at first ...
So in my experience the first place where they develop rust is on the "lock-release buttons", and the ones on the Spirit take longer to develop rust on them, probably because the ones on the Swisstool are more "ribbed" (is this the correct word ...
) than the ones on the Spirit.
But yes, they do rust, but still not as easy as the Leatherman tools ...
.