I cannot believe that the human brain somehow makes the installer tighten the line conductor more than the neutral.
You can believe it. It is something in the sub-conscious "auto-pilot" where "emotion" affects and overrides physical ability / activity. If you can walk along a two inch wide beam one foor above the floor without falling off then you can walk along the same beam 50 foot above the floor without falling off. Try it.... most will fall from 50 foot. Some will say feed back from the view via the eyes affected the balancing process. This led to the experiment being conducted with people blindfolded. They could walk the beam one foot high but most lost balance when 50 foot above gound. ( safety rope saved them )
The Live terminal is more dangerous ( 50 foot high ) than the Neutral ( one foot high ) so the Live probably gets a bit more tightening even if the person doesn't realise it.