The ABC agents are obviously not correctly trained law enforcement officers. Even in "undercover" operations, police will have a mix of plain clothes and uniformed officers to avoid situations like this.
They need to have better procedures in situations like this. A woman at night being approached by a bunch of men? The cons of staying are far greater than anything that could justify it. Sadly these situations happen so late that once the arrest is made, there is nothing that can be done until morning. That needs to change somehow.
Protect yourself from police abuse. There was a similar situation from an ABC agent for a different state(NC):