Okay! I think that makes sense. What about situations where there is a 0 in the button field? Is zero mapped to going forward or is zero just a place filler here? This is an example I found from you on a different thread that has a zero in the button field:
# Send a positive x value for 5 seconds.
# http://mavlink.org/messages/common#MANUAL_CONTROL
i = 0
while i < 10:
master.mav.manual_control_send(
master.target_system,
500,
0,
0,
0,
0)
time.sleep(0.5)
i += 1
sys.exit(0)