The witness gifts of mercy are........wait for it...........field service. Now I know some enjoyed it but for the majority they hated every second, so why did they do it, even more than was required = 10 hours) Because it salved thier conscience, they had done their hour or bit for humanity.
Most JWs know they should be doing charitable works, and some do.
And as for the trumpet blasting, how much more in your face can you get with car loads of Jws swarming on a territory. Saying "here we are, while your all in bed tut tut, look how dedicated and christian we all are "