Hi everybody!
I own two Contax 167 bodies, so I'm VERY interested in this debate.
I think that the "linear polarizer question" depends from the sensor topology of your camera.
For instance:
Contax ST: has two sensors, one for flash metering and the other for C/W and spot metering
On the diagram I coud not see any half mirror; flash metering is taken directly from the film, and normal metering (spot and C/W) is measured from an SPD behind a glass prism (they call it "aspherical lens", because one of the surfaces is aspherical).
Looks like the metering switch (C/W vs. spot) is done electronically... right?
If not, how can the meter cange measurement type? I see no mirror, and I can't imagine another way...
Contax 167
It looks even simpler, the C/W and spot SPD is on the main prism.
Contax RTS III: ouch! This camera has THREE sensors...
...and problems with linear polarizers.
Can you see the spot SPD under that mirror? Go buying circular PL... now! :^)
Contax RX: same as ST, but AF sensor could get confused.
So: it looks to me that 167 and ST should not have problems with linear polarizers.
But I'm not shure.
Sometimes I get one or two overexposed shot with my 167s, I always attributed them to "forgotten" memory locks, as I use polarizers quite rarely...