[Tagging] towers, why limit communication towers to 2way and broadcasting?

[Martin Koppenhoefer]

The current text on
http://wiki.openstreetmap.org/wiki/Tag:man_made%3Dtower#Tower_types
give this definition for tower:type=communication:
"Communication towers which are used for broadcast or two-way
communications via radio waves; such as radio, television, cellphones
and two-way radio." which does exclude receivers. Why shouldn't
receivers be tagged like this? Should/could we amend the definition?
Currently there is no documented alternative (AFAIK) for towers that
only act as receivers.

cheers,
Martin