Actually Mike, this 'issue' occurred two years ago as well. Speaking with umpires who called the tournament, the problem is not ASA, but the ISF does not have enough inventory of 'logoed' gear for the crews.
In Canada last year, all the crews received 'proper' gear for both on and off the field, but for some reason, ISF does not do this for the World Cup games.
I would rather see them wear ASA uniforms, than 'blanks'