Interesting subject. I don't think that my ear is good enough to hear if a string is 2 or 3 cents out of tune. Will always err on side of slightly flat. Flat notes can be 'bent' into tune while playing but sharp fretted notes can't be adjusted downwards whilst playing.......and, in my opinion, slightly sharp notes just clash/sound worse than slightly flat notes.
(All of this from a bloke who tunes his bass a semitone up from 'standard' EADG anyway).