I have tested that theory.
I took a fly, sat it on the table, I screamed, "Flee FLY!",
and the fly flew away.
I then took a fly and pulled one of it's wings off and sat the fly on the table,
I screamed, "Flee FLY!", and the fly took off scoot'n across the table.
So then I took a fly and pulled off both it's wings and then sat the fly on the table,
I screamed, "Flee FLY!", and the fly just sat there. So again I screamed, "Flee FLY!", and the fly still just sat there.
And thats how I came to the conclusion that fly's without wings are deaf.