That sort of exposed circuitry is not a real good idea. That said, as long as the HV is supplied by an isolated source such as a transformer, it's probably not a usually-lethal threat. The reason is that the HV is carried on conductors which are close together, and the most likely accident will involve a current path through the fingers of one hand. At 170 volts, this will be painful, and possibly result in burns, but there will be no path through something critical like the heart.
Of course, there's always the possibility of grabbing the board with both hands and getting unlucky. The problem with making things foolproof is that fools can be so very clever.