Pick off at first

Basically two things to make this okay, either throw to the fielder that's "close enough" in the umpires judgement or throw to the bag.
So no, F3 does not have to be on the bag when a PO is started.

FED and OBR are different in this regard.

[QUOTE]Originally posted by Jimmy03:
FED and OBR are different in this regard.[/QUOTE

please explain, this was a high school freshman game.

Can't quote the FED for ya.

But a couple examples would be F3 playing deep and behind the runner or say charging towards HP when F1 makes his move, if he were to throw to F3 who's now to far away for a play at the base he's getting balked in any code.

If he leads F3 and throws to the bag he's okay, whether F3 get's there or not.

If F3's just playing off the bag a step or so and he's close enough for the tag, no problem.
A legal tag attempt on a 6' runner diving back could have F3 what, 7' from the bag. F3 doesn't have to tag the bag, just the runner.

From the casebook:

6.2.4 SITUATION J: With R1 on first base and two outs, F1 attempts to pick off R1. As F1 pivots to throw, he realizes that F3 is not on the base, but is in his normal defensive position. F1 completes the throw without interruption. The coach of the defensive team wants a balk called on F1.
RULING: As long as F3 is in the proximity of the base, F1 would not be guilty of a balk. Proximity is umpire judgment and is based on whether the fielder is close enough to the base to legitimately
make a play on the runner.