Protesters are commonly bused in to make a protest seem full of locals who support it. Certainly possible that is going on for the unrealistically large Harris rally.

'Megan Thee Stallion' has been selling out arenas, and recently had to cancel two shows in Atlanta. No doubt she is why so many are at the Harris rally.

June 1, 2024: "Sold-out Megan Thee Stallion concert canceled for second night, no word on rescheduling She was scheduled to perform on Friday and Saturday, but couldn't after water main breaks in the area. The rapper says she still wants to perform for her fans in Atlanta."

https://www.wsbtv.com/news/local/atlanta/call-mayor-megan-thee-stallion-tells-fans-she-still-wants-perform-atlanta/L32EB2TMPZDGBL5O5X4XFYQM7M/

Ossoff calling President Trump and Vance, "strange men with dangerous ideas" at the Harris rally.