As much as I don't want to have an argument, I think that's (with respect) a bit harsh TDK. As a mere 'passenger' should I therefore apply this to other situations, such as the one I witnessed (and was very nearly involved directly in) where a Northern Rail guard released all train doors on a short platform in the pitch black, resulting in people only at the last minute realising there was no platform next to the door and climbing down and walking along the cess? By your argument, he's a professional, so I shouldn't stop and query it because it's none of my business.
Don't get me wrong TDK, I'm mostly a lurker around here these days and I find the vast majority of your input very useful and insightful, but that does seem incredibly arrogant and unfair on the chap.
Although yes, 150222, you are fussing a bit over nothing.
In addition, some first gen DMUs (including at least some 101s) are and were fitted with return buzzers - perhaps not from new - although I wouldn't be able to give which specific ones.