Federation rules.
Runner on first, one out.
Grounder toward the 5-6 hole. SS chooses too deep of a route for the so-so speed of the ball, then bobbles it. With no chance of getting any runner out, he makes a pointless desperation throw to second base.
R1 easily beats the throw, but makes an illegal slide, going beyond the base and then making contact with the second baseman.
So, R1 is out for the illegal slide. There's no malicious contact. It was just poor technique.
The question is whether the batter-runner is also out.
It may seem obvious that the batter-runner is out because we know the force play slide rule says the call is interference, and with less than two outs the runner is declared out, as well as the batter-runner.
There are two problems with the obvious answer:
1) There was no play to interfere with. Because of his poor technique and fielding, the shortstop had no play anywhere. And neither did the second baseman, who had acknowledged as much by receiving the throw positioned like a first baseman with his right foot planted on the left field edge of the base and his left foot extended toward the source of the throw. He had no thought of any follow-on play.
2) It might not have been a force play, but the imprecise wording of the Fed rule book leaves room for doubt. Rule two defines a "force out" as a putout during which a runner who is being forced to advance is put out by a fielder who holds the ball while touching the base to which the forced runner is advancing." It does not define a "force play," and reasonable people could differ on whether a force play is a play on which is force out is recorded or whether it is a play where a force out is attempted. In fact, a quick review of plain language dictionaries finds it defined both ways in normal English usage. So there is some ambiguity.
At what point, if any, can an umpire say the hopeless throw was so late that it was no longer a force play and there was no interference because no fielder contemplated any follow-on play?
Does the force play slide rule's primary purpose of protecting middle infielders from being taken out while they make the relay to first have any bearing on the interpretation?