my last mtb/touring bike had a regular rear kickstand, clamped to the chainstay
with an arm that went up to clamp onto the seatstay. worked well even with
loaded panniers (20 lbs). i just put the new bike together, with a rear disc that
limits the type of kickstand (if any).

the BMC frame has these two boltholes on the chainstay to mount a kickstand.
so i got one as pictured, bolted on, and hooray it works. BUT.....how much
leverage or torque will that there kickstand apply to the chainstay? i assume
there were engineers, smarter than i, who designed this thing, aware that it
could/would be used with loaded panniers.

it just looks a little scary. i'd hate to be on tour in cambodia, put the bike on the
kickstand, then have the chainstay snap. anyone heard of someone who read
about an urban intenet rumour of someone who's kickstand cracked/bent their
chainstay?

p.s....the shark fin is a billet aluminum rack mount. those same genius engineers
designed dropouts that wouldn't allow mounting a standard rack.

So you are requesting rumors and hearsay, as I read it?

Koga Miyata And Tout Terrain,also use a KS mount in that location.
and I note the Plietcher 'zoom' model, which Is, via bolts between the foot
and the rest of the stand, is adjustable in length..

seems to me,that is how the torque is controlled, how far off center the bike is leaning.

[I have the Zoom model for mounting on the central KS plate.]

The way it is arranged i don't think that significant torque will be applied by the kickstand, only a compressional load along the axis of the stand tube. The only way to apply torque would be to grab and pull the stand and use it as a lever; even then you would have to pull pretty damn hard to even flex the chainstay, much less "snap" it.

If you are going to replace logical thought and basic physics with concern about urban internet rumors you had better stay home at your computer where it is safe.

there are lots of neat gadgets that are great in theory, not so great in practice.
i've never seen a mount like this....pretty rare in this part of the world.
maybe it was groovy popular for a year, then abandoned.
so if someone had one, loaded up their touring rig, and damaged
their aluminium bike, would they admit it? course not. they'd say
they knew a friend who............

and here's a logical thought: bicycles are often left in the main reception
hall in hotels here in asia. desk clerks get bored, like to play on the big
foreigner's big bike. they'll often be seen sitting on a parked bike with the
kickstand down. what's the compressional load of a 140-pound vietnamese
desk clerk jumping on the shoulders of another 140-pound vietnamese desk
clerk sitting on a bike with the stand down?

Noe we are getting somewhere, moving from urban internet rumors to speculative anecdotes.

A simplistic approach to quell the concern would be bend the kickstand a bit then straighten it back out. That way if to much load is applied the kickstand will fail fist.