Interesting debate. I'm used to rest my thumb on some string, or deliberately mute basses with it, or let the finger float above them if they should resonate. For me, it would cost extra energy to move the hand, not to keep it in place.
2014 Martin Okenica cedar, modern (H. Hauser I inspired)
2012 Martin Okenica spruce, early romantic (F. R. Lacôte inspired)