Does this setting do anything, or is it merely ornamental?  

I had two runners tossed out at home in the 2nd inning of a 0-0 game:

whatifsports.com/slb/Boxscore.aspx

Both runners are slow (one has a 44 speed rating, the other 58).  

My Base Running Aggressiveness setting is 1 (the lowest possible #).

I could understand this maybe happening in the later innings of a close game, but in the 2nd?  

My anecdotal experience is that Sparky uses the Base Running Agggressiveness setting as more of a guide to base stealing than other baserunning.  For all the current  emphasis on pitching in OL's, Sparky likes to see scoring,  and he doesn't play much station to station baseball.  Nearly all runners try to score from second on a single to the OF, regardless of setting, speed or game situation, and most runners try to score from first on a double.  Advancing on a sac fly and going from first to either second or third on a single seem to be the only baserunning moves (other than steals) that are genuinely influenced by the Baserunning setting and, even there, Sparky seems to "dial up" better than he dials down.  A Baserunning Aggressiveness Setting of 4 or 5 virtually ensures that the runner (even slow ones) will try to take the extra base while a Setting of 1 or 2 doesn't ensure that he won't try. 

I also wonder whether Baserunning Aggressiveness has an impact on double plays with higher settings causing more runners to break up double plays (even if that isn't described in the play by play).

Thanks for the post.

 Yes, the 1 setting does seem "dialled up" inasmuch as I read most of the play-by-plays of my games and notice quite a few runners being thrown out on the basepaths (and I always use a 1 setting for Base Running Aggressiveness).  With the team in question, I have very slow runners who have decent walk and HR totals in a theme league with no deadball pitching -- I don't want them thrown out at home in the 2nd inning, I want them sitting on the bag waiting for a home run.

Still, I don't think this setting is used to influence base stealing.  Even with the 1 setting, I never noticed a drop off in attempts for those runners who had a 5 Base Stealing setting.