Bart
The only reference I find to fan interference is here. It does not really apply to this situation, although it would if a fan were totally on the court trying to interfere. But I think the discretion clause in this rule definitely rules out penalizing a team for the foot in a situation where there is no room for spectators.
Rule 2
SECTION 8 OFFICIALS' ADDITIONAL DUTIES
The officials shall:
ART. 1 . . . Penalize unsporting conduct by any player, coach, substitute, team attendant or follower.
NOTE: The home management or game committee is responsible for spectator behavior, insofar as it can reasonably be expected to control the spectators. The officials may call fouls on either team if its supporters act in such a way as to interfere with the proper conduct of the game. Discretion must be used in calling such fouls, however, lest a team be unjustly penalized.
Now I agree that if the foot in question didn't jump back in reaction to what happened on this play, you may need to deal with the fan to get them completely off the court. My ASSumption (we all know about those
) was that this fan would react like most and pull his/her foot off the court after it was hit by the ball. If they do pull back, no reason to stop play, IMO.