an experienced bike painter/powder coater, IME (and i've had a few bikes repainted and/or powdercoated) will not allow the paint to enter the headtube to the extent that it will interfere with re-assembly and if any gets in there it should be easily removed with a bit of hand sanding. as for refacing, i've never had to have done to any of my bicycles and most of them have been purchased used and then refurbished.

OTOH, i would make it a point tp ask anyone i considered to repaint a frame/fork, whether or not they had any experience painting a bicycle frame/fork, if they say "no" i let them down gently and move on.