I think this is one of those "theory vs. the real world" arguments.  It
reminds me of the time I got in an argument with an electrical engineer
about single-sideband radio.  He insisted that single sideband
transmission couldn't be done, that you couldn't make filters that sharp.
I pointed out that I'd talked on single-sideband radios on many occasions,
and that they worked just fine.  Of course, they weren't, strictly
speaking, perfectly filtered -- but if the unwanted sideband is attenuated
more than 40 dB from the desired signal, who cares?  It's effectively
gone, for all practical purposes.

David Brodbeck, N8SRE
'82 Diesel Westfalia
'94 Honda Civic Si -- For Sale
'86 Volvo 240DL wagon