Quite right, obviously there's a big difference between using a note pad as an aide memoire, (I don't think many people would pull out a cumbersome tech log en route to fill in the defects) and the note pad taking the tech logs place for the engineers purposes. I am fortunate to work in an environment where there is no discouragement to make defect entries, but I guess this is not always the case elsewhere.
I feel discussion with an engineer is useful though; eg 'we have this problem with this and this, what do you think it is' - it can help make a more useful entry including say, info that otherwise would have been considered irrelevant.