Attendees of Trump rallies have to sign waiver, can't sue if infected with Covid-19

Attendees of future Trump rallies have to register before the event and must agree to a disclaimer that they are aware of the "inherent risk of exposure to COVID-19 exists in any public place where people are present" and that they can't hold the Trump campaign liable in case they are infected with Covid-19.
The disclaimer reads: "By attending the Rally, you and any guests voluntarily assume all risks related to exposure to COVID-19 and agree not to hold Donald J. Trump for President, Inc.; BOK Center; ASM Global; or any of their affiliates, directors, officers, employees, agents, contractors, or volunteers liable for any illness or injury."