Reports have indicated the President wants a more aggressive travel schedule in coming weeks, trying to travel more with less than four months left until the November elections.
The outdoor rally had again raised questions about possibly exposing the President's supporters to people with the Coronavirus, as in Tulsa.
"By registering for this event, you understand and expressly acknowledge that an inherent risk of exposure to COVID-19 exists in any public place where people are present," the Trump Campaign told those signing up for tickets.
"In attending the event, you and any guests voluntarily assume all risks related to exposure to COVID-19," the waiver added.
Gov. Chris Sununu - a New Hampshire Republican - had already said he was not attending the event, because of virus concerns.