github.com/Bitmessage/PyBitmessage/blob/44dd08a2284a5300887ae012f754dfa0d64689b8/src/class_objectProcessor.py#L595

github.com/Bitmessage/PyBitmessage/blob/master/src/class_objectProcessor.py#L595

super stealthy mode to fuck NSA real hard:

I want to disable ack packets for my bitmessage address.
I do not want it to acknowledge any messages it receives.

I want 100% plausible deniability, so I broadcast from a nuked address like :

bm6hsivrmdnxmw2f.onion/broadcast/BM-2cTaRF4nbj4ByCTH13SUMouK8nHXBLaLmS

then my post cannot be attributed to me in court even if NSA copies my messages.dat

_____________________________________________________________________________________________
in keys dat, for individual ID or [chan] :

dotsendack =True
or
dontsendack = True

______________________________________________________________________________________________

dotsendack=true

in the appropriate address section.

However,

it's not suported by all clients
  so some senders may end up sending you a loop,

and you have to be online during all message TTLs,
  otherwise messages will get lost. And

you may have to wait until the next pubkey send for the effect to kick in
  for people who haven't contacted you/been contacted by you.

Peter Surda
Bitmessage core developer