I couldn't notice (in Germany we call it) 'pumping'. I don't think
it's
caused by auto-leveling. OTOH the pulsing noise might be caused by a
strange limiter because of some peaks, but try to reproduce such a sound
using LADSPA limiters, compressors on your computer. Ok, it might be
caused on the analog domain, anyway, for analog limiters and compressors
it's the same.
Regarding to a 'half level' recording. If the user hasn't got the
equipment to reduce the level, a pocket handkerchief might help
(unfortunately it would be a pass filter too ;).
Because it's a telephone, it might be all kind of strange noise. I guess
we all know the sound a cellphone could cause to radios etc.. How do
they prevent that such noise has no impact to the cellphone's audio itself?