Trump's audience inside the coliseum was 6,500, at capacity, El Paso Fire Department public information officer Enrique Aguilar told the El Paso Times. "It might be 10,000 with the people outside," watching on monitors.
The rally O'Rourke spoke at, following a mile-long march, drew at least 7,000 people, The Texas Tribune reports. Bloomberg's Jennifer Epstein says that's an undercount:
Jennifer Epstein
@jeneps
El Paso police estimate a crowd of 10,000 to 15,000 for the anti-Trump, anti-wall, pro-O’Rourke march and rally tonight.
http://theweek.com/speedreads/823268/trump-seemed-interested-beto-orourkes-evidently-larger-crowd-during-el-paso-rally

DO SOMETHING!