Most meters are quite accurate. I use a "modified" zone system, spot metering particular areas of interest if I think they are significantly different from what I would expect, thus requiring exposure adjustment.
Some folks will go ballistic if they think a meter reading is off by 1/10th of a stop (I don't know how they know that).
This is total hog wash. The film and the rest of the process would never notice such an error.
As to the actual magnitude of the UV/IR problem, let's look at the solar spectrum at the Earth's surface (red curve):
Ref: Wikipedia Sunlight/Composition: http://en.wikipedia.org/wiki/Sunlight#Composition
Note the UV/Visible/Infrared captions at the upper left of the graphic.
Note also the extremely low amplitude of the UV energy as compared with the visible.
Infrared energy extends quite a distance below visible, but that greatly exceeds the spectral sensitivity of general-purpose film.
The film sensitivity curves that PE posted in #4 and those that Bill posted in #5 show no sensitivity below 700nm.
If any UV/IR sensitivity exists, the available energy is only a small fraction of the visible energy that controls the meter.
My assessment: Picker found a solution looking for a problem, and provided biased analysis to support his product sales.
Yes, there might be a slight difference between meter readings in the general case, but not enough to worry about.