Police issues a dispersal order, but blocks all routes to safely leave the area.

Congratulations, you will now be charged as having committed a crime and good luck proving in a court that there was no realistic option for you to leave.

Also police seizes your phone. Congratulations now they access your data and either go after people you have had contact with or they claim you to be part of a criminal organization as they pin other charges on people they found a connection with.