The issue that I had/have with this conservative mind set is more that could it inadvertantly get you into trouble? (Otherwise I have come to accept that some guys are actually way to anxious in the flight deck)
Specifically, in the case I am referring to I noticed a 10-15 kt drop in takeoff speeds after going 'conservative'. The issue is what are the implications in the event of an engine failure? The slower ground speed? Lower V2?