'Tis true brother Andrew. however, remember on that one that although the PGMII started smoking (scary!) the RC valve were still in operation. Wierd.
I think the answer to all this is that these bloody bikes are so ahead of their time (even the lowly MC18) that if you even just look at them from a funny angle they're likely to blow a fuse!
So I would say that in your regular maintenence schedule you should include inspection of the TPS among all other things. Check that the resistance slides up and down the scale smoothly and doesn't jump about. A squirt of WD40 or something might help keep any potential corrosion at bay. If in doubt, change it. I'm sure that they're easy to get hold of in good condition, used.
If it's gone to ruin already then it may not come back to life. I tried to ultrasonic one TPS in an attempt to resurrect it, but it had no effect.