I had a twinge of deja vu re this topic, confirmed by a search of the term on the AMA website. From the Apr '07 EC meeting minutes:

"MOTION IX: Moved by D. Mathewson (II), seconded by T. Stillman (V) to accept the recommendation of the Insurance Committee to approach our insurance company to modify language in the Westchester General Liability Policy to provide primary general liability protection to officers of AMA Chartered Clubs in good standing for vicarious liability for the actions of others.
*Note: This additional coverage is for the five officers listed on the club officer sheet, i.e. President, Vice President, Secretary, Treasurer and Safety Officer (coordinator), this is assuming that one of the above officers is also named as the contact person for that club.
MOTION passed: 12-Y; 1-Abstention (NAA)"

So, the concern of vicarious liability has been addressed by AMA. I didn't continue the search to verify that the insurance company has actually added this coverage.