Logical gap

Here's a question-

assuming Sheriff  Dupnik is correct, and talk radio plus the immigration issue has created a dangerous atmosphere in Arizona, why would his department let a US Congressman hold an outdoor, public townhall meeting with no deputies present? 

"When the rhetoric about hatred, about mistrust of government, about paranoia of how government operates, and to try to inflame the public on a daily basis, 24 hours a day, 7 days a week, it has impact on people especially who are unbalanced personalities," Dupnik said Saturday night. 

For perspective, here in Steele county Minnesota, any public gathering where alcohol will be served must have a paid sheriff's deputy present.  Wedding reception with beer?  You need security.  Street dance downtown?  You need the law present.

Yet in Pima County Arizona, apparently you can gather hundreds of people in a Safeway parking lot, who are all there to discuss politics, and in the middle of this 'paranoia' and 'rhetoric about hatred', the top cop didn't feel the need to have even one officer present?