Earlier quoted context omitted.
I suppose I'm left wondering if this causation loophole - a properly engineered switch being deemed not to cause anything, despite an obvious cause/effect linkage to an observer - is usable in other, nastier scenarios. Can I (setting aside the obvious secular punishments for a moment) murder someone with a bomb activated via one of these switches?
IMHO those are not comparable scenarios. In the case of murder, the result and intent is prohibited, so no matter how you get there, that's a sin. In the case of having a fire on Shabbat, there's nothing wrong with wanting a fire or having a fire, the result is not prohibited or a moral wrong; but in that particular time and place you are prohibited to light a fire. A hundred years ago the standard solution was to si…
That sounds like a bad incentive. If a shabbos goy decided to convert he would have to stop being paid, which means that you would be paying the shabbos goy to not convert.