Running to 1B on a Dropped third strike

[UMPIRELARRY]

I was umpiring a Fast Pitch game a few weeks ago and encountered a 16U team whose players always ran to 1B on a 3rd strike, regardless of whether or not the ball was dropped, and regardless of the situation (i.e. even when 1B was occupied)? Obviously this is done to confuse the defense into throwing the ball around, but at some point does this amount to interference? For example, there is a runner and 1B and less than two outs, the batter strikes out then runs all the way to the bag. At this point there are now two offensive players at the bag along with the first baseman who may be in the process of trying to make a play on the runner who was lawfully at 1B. Go one step further. What if the batter above ran to 1B and then rounded the bag. Is this a form of interference? The batter is out and is not supposed to be in fair territory, let alone become involved in an on-field play. ANY THOUGHTS?