Is there any evidence that the girl in question committed a crime?
If someone is interfering with an officer's ability to control chaos at a scene of reported crime then that person is subject to arrest for interfering with a police officer discharging their duty. Often what happens is the individual is neutralized and when things calm down they are released. Just because a person is cuffed does not mean they're going to be arrested for criminal interference, but it is a criminal offense nevertheless.
By "neutralize" I mean an action that essentially removes an individual from interfering. If too many people are meandering around causing needless distraction the neutralizing act might be an instruction sit down and stay in place. If the person complies then that person is no longer interfering. Alternately the same person might be asked to get out of the scene of investigation. Basically this means, 'Remove yourself from the chaos so I can watch for dangers yet unidentified.' If the person complies then any interference they were causing is likely to be neutralized. When someone is doing something that interferes with a police officer carrying out their duty and does not comply with instructions that would remove that interference, the individual will likely find themselves being physically restrained because the officer has other fish to fry and he or she needs to act for the individual who refuses to act responsibly for themselves, the police officers and everyone else's safety.
In the McKinney pool party incident my opinion is the bikini clad gal was interfering with police attempting to control chaos at a scene where violence had been reported.