Which situation would be a violation of Standard A30?

The situation that represents a violation of Standard A30 is when a volunteer is vaulting without an ASTM-SEI helmet. Standard A30 emphasizes the importance of proper safety gear, particularly helmets that meet ASTM-SEI standards, when participating in activities involving horses. Vaulting is an activity that inherently carries a risk of falling or injury due to its dynamic nature, making the requirement for a properly fitted helmet essential for the safety of the participant.

In this context, the absence of the appropriate helmet during such a high-risk activity demonstrates a clear violation of the safety regulations outlined in Standard A30, which is focused on ensuring the safety of all individuals involved in equine activities. The other scenarios do not violate the standard regarding helmet use in the same manner. For example, driving while wearing a helmet or having a mounted staff member with a helmet does not contravene the standard as they are either participating in different activities where helmet use is appropriate or compliant. Grooming a horse, while a necessary activity, does not typically require a helmet. Therefore, the choice of a volunteer vaulting without an ASTM-SEI helmet directly violates the critical safety provisions intended to protect participants during equine-related activities.