These days it's smart to have them sign a waiver (there are occasional lawsuits; they're not well publicized).  You can get what you need in a waiver and it's common to do that (e.g., at conferences).  My waiver is very short and says three things in plain English (paraphrasing, as a lawyer has not reviewed mine yet):

1. This is an energetic physical activity with people touching people. All such activities carry inherent risk of serious, permanent injury or death (e.g., from Covid or another communicable disease, medical conditions known or unknown to the participant, and many other reasons).  You assume these risks and covenant not to sue the organizers, caller, venue, etc.

2. People will take pictures and record audio and video, and may post those publicly or use them commercially.  You acknowledge and agree to this, and waive all related rights and compensation.

3. Dances depend on good social behavior.  You agree to interact appropriately and to read and follow the posted rules and callers' and organizers' instructions.

I was at one dance where a newbie swung her arm over her head to get into a swing. She elbowed her boyfriend in the mouth and chipped a tooth.  Carry insurance and use a waiver!  The CDSS, NFO, and Callerlab all offer insurance for callers (Callerlab also has ASCAP and BMI licenses, for those using recordings).

--jh--