Right on cue, you're ridiculing the slippery slope argument. But you know that this case is going to result in a decision, which will be a precedent in future cases, based on which creative lawyers on either side will bring cases, seeking to push the boundaries of the law one direction or the other. That's how it works, as you know.
This is all political anyway. Supreme Court decisions amount to politics, buffered by the appointments process. If there are enough justices on the Court who want to find a way to get to the bottom of that slippery slope, they will.