Balk???
 

Pitcher wheels and attempts to pick off R2. Neither the F4 or F6 is covering. The pitcher steps toward 2nd base and throws the ball to F6, who is routine position. Is this a balk?

OBR = No

FED = No

JM

NCAA = No

Answer to the topic of this thread = no

It would be if the throw was to F5, with R2 and 3B unoccupied?

That would depend. In OBR F1 may throw to an unoccupied base to make a play. In FED, F1 may throw to an unoccupied base to make a play OR drive back the runner.