On the "Saturday - Workshops" pdf of the schedule (having finally printed it out):

"Public Checkrooms"
"A public checkroom is available for your convenience in the Fisher Pavilion Roadhouse. Hours are Friday through Sunday, 11am-10pm and Monday, 11am-9pm. The cost is $2 for once-time check and $5 for unlimited access."

So, that's the dance hall zone, and presumably instruments are checkable.

~ Becky in Tucson