Snatch & Grab - does Runner take a trash to prevent trace or to prevent result of trace? Can the Runner prevent the tag w/ NACH?
is the key difference "X to Y" vs. "Y unless X"? "To" implies cost?
Effects written as "do X to Y" should be read as "do cost to effect." This means that if the first part of the effect is prevented, then by the nature of the cost being prevented the effect is also prevented.