No one on here is stupid, are you or is it just your natural arrogance?, we tend to make up our own minds about such matters.
Your profile says 6745 posts so you have been around for a while and you say no one on here is Stupid
Stupidity is all around us, we all a guilty of it from time to time myself included. We all know there have been posts that make you wonder why the person concerned is allowed out on their own.
To me, and I accept these things are subjective, refusing to believe the huge weight of evidence that the type of fluid being discussed needs regular replacement is stupid. It can't really be called ignorance as the people concerned have heard there might be a problem.
You use the word arrogance, for my part it appears that thinking you know better than others might be one definition of that term. So are not those who, without scientific evidence, hold that the entire motor and motorcycle industries are wrong on this and that they are right, might they not be called arrogant?
As you may know I worked on Citroen cars for many years, 40 odd in fact with 30 of those running my own repair business. Citroen solved problems they were having using a variation of conventional brake fluid by changing to a mineral fluid (1967). These vehicles had high pressure hydraulics used for brakes, suspension, gear changing and clutch operation as well as steering
Most of these problems were caused by the hygroscopic nature of the fluid and the corrosion caused internally by this. If you look at many parts of the system you will see that there were often no seals. It worked because of the close tolerances used in manufacture. Therefore small amounts of corrosion caused things to sick and hence fail. From the point that Citroen change other cars in the range away from normal brake fluid we saw no further problems with things like leaking rear wheel cylinders. If you want to look for a conspiracy in the trade you could do worse than asking why, when there was an alternative, they continued to use an inferior fluid.
Since moving here and setting up our biker hotel I have replaced fluid on a number of guests bikes. Usually it can be described as "brown trouser syndrome" A guy come back, white faced, telling of how his brakes failed coming down a pass. On inspection everything looks in order (and I do know what I am looking at). If there is no other fault in the system such as a fluid leak then the logical explanation for the lever or pedal having had no resistance but since recovering is brake fade. This is caused by the fluid turning to a gas by the effects of the heat generated under braking. It is a fact that with age the fluid absorbs moisture and the boiling point therefore reduces, in extreme circumstances this will manifest as brake fade. Often I find it is the rear brake, people tell me the fluid was replaced in the front but not the rear! After the fluid is replaced the guests go on to report no further problem even when, as some have done, they try to provoke it.
I am sorry if I have caused offence, or indeed bored to death those of you who have got this far but I maintain that we are talking about a safety issue. Were we discussing the rights and wrongs of replacing an alternator belt for instance as a precautionary measure, then I would be with you 100%, In that case it would be up to each of us to weigh up the risks involved and decide as grown ups, what to do. There is little chance of injury to self or others if we get it wrong.
That is not the case with the risk of brake failure, we cannot choose when an where this might happen or who else might unwittingly be involved. I therefore ask that the sceptics look again at the evidence concerning the nature of brake fluid and not just say things like " Well I haven't changed fluid in 20 years and I am still alive" or " I don't understand how the moisture gets in" I would say to the former, you are lucky but then so is the man who played Russian Roulette and lived (and I know that is an over dramatic example but I hope you see the principle), to the later, not understanding how something happens is not the same as knowing it can't happen.
John
. Modern brake systems are as far away from that as an old mini A series engine is from a modern engine with its fully managed fuel and ignition systems. 
