The USASF Rules Glossary received a significant upgrade this summer and is now included as part of the Rules PDF file. Within that upgrade the definition of spotter has been updated and now states (in part):
May not be considered both a base and the required spotter at the same time.
Example: In a two leg stunt, the base of one of the legs is not allowed to also be considered the required spotter (regardless of the grip).
This update makes the show and go in the video below ILLEGAL in Levels 1-5 for not having the required spotter. The male base in the video placing his back hand on the back of the top person’s ankle no longer allows him to be considered the spotter. The skill would need an additional person meeting the definition of spotter to be legal in Levels 2-5. It would need to stay at prep level or lower and have an additional person meeting the definition of spotter to be legal in Level 1.
Note – The information in this article is based on the August 27, 2015 release of the rules.