Triple play?
 

Just looking for opinions because it was a bit of a debate at a rec game last night...
Runners on first (R1) and second (R2) - 0 outs...
Batter (B1) hits a line drive up the middle that just skips on the ground just before SS fields it.
R2 returns to 2nd thinking ball has been caught.
SS tags R2 (while R2 is on 2nd base) touches 2nd base with foot (before R1 reaches 2nd) and throws B1 out at first.

Triple play or R2 safe at 2nd base and R1 and B1 out?

Triple play.

Because F6 (shortstop) tagged the runner first, it's a triple play.

If she'd have stepped on the bag first, then R1 (in softball rules parlance, the lead runner is R1, the next R2) could have remained safely at 2B with 2 out.

Well, color me thick, but I don't get why this is a question. What was there to debate here? Pretty straightforward - R1 out, R2 out, BR out in that order. (Switching the runners to softballese).

The question was whether or not R1 (softballese) is allowed to occupy the base until R2 arrives or if once the ball is in play then the base no longer belongs to the runner, who is forced to advance.

Ah. Guess you have your answer by now... :) No, in any ruleset of baseball or softball. Ask yourself this ... on a forceplay, can the runner simply stay at their original base to avoid being put out at the base they are forced to advance to?

At the risk of being redundant. . .so long as the force is 'on', R1 cannot avoid being put out by staying on his/her original base. So as described in your OP, the fielder properly executed the triple play by doing things in the correct order--tag R1 while still forced, then tag 2B for the force on R2, then throw to 1B for the BR.

Sometimes, fielders screw up and tag 2B first, which puts out R2. Now R1 is no longer forced, so if R1 is tagged on the base, it is nothing.