Because the proper response to "was that for N12345" is from the
controller, and is either "no" or a repeat of the call.

What, exactly, is the PROPER response to "blocked"? Both the controller and
the blocker repeat and do it again?


Peter R. wrote in
:

SeeAndAvoid wrote:

snip
If you think your callsign was part of that call, ask "was that for
N12345?".

Only having a few hundred hours in busy Northeast US airspaces such as
New York and Boston, I have to ask: How is asking "was that for
N12345?" less troublesome on a busy frequency than calling "Blocked" or
better yet, not saying anything at all and waiting for the controller to
call again?