IMHO, the selection of flap for take off is both critical and forgettable, thats why there is a this warning. This is particularly so, if for example, the flap selection has to be delayed until just prior to lining up, just post de-icing.
The operation I work for does autoland the 737 classic and NG. Flap 40 is the recommended setting as it gives a lower nose attitude and therefore a greater chance of seeing some lights, but flap 30 is certified.
Am dumbfounded that an aspiring "professional" aviator is suggesting that someone sitting in the back drinking beer and eating peanuts should report fellow professional flight crew to CASA. What has happened to the world.
I bet they would make a helpful and supportive F/O, NOT!
BB