Police powers and your rights
More often than not at a protest event, protesters have some interaction with police.
Interactions can be physical, verbal, hostile, or unremarkable. Whatever the context, it pays to know your rights and responsibilities with police: when you must do what they are asking, when you can refuse or walk away, and what powers they have To make people obey (a law, the terms of an agreement, etc). Also: enforceability. the law against you.
A discussion about different police tactics at protests can be found here.
It is also important to be aware of what obligations police have when dealing with you. Police do not have unlimited powers – they must use their powers in line with the law.
If the police have not followed law or proper procedure this may be relevant to your court matter, if you want to bring a case against the police, or if you want to make a complaint against the police.