In all seriousness...
Protests aren't wrong, but despite this the police are still often sent to break them up. The
Green & Black Cross have the following
key pieces of advice for protestors when dealing with the police:
1. Under Stop & Search, you don't have to confirm your name.
2. You can always ask police "what power?" they are using and why.
3. Give "no comment" to all questions.
4. If arrested, arrange your own solicitor (preferably from the
Netpol recommendations). The GBC legal hotline can help at
07946 541 511.
5. Never accept a caution (except under advice from a solicitor).
None of us are criminals (I hope anyway!), so it would usually be fine for us to be friendly and cooperative with police. Protests are a little bit different. While I'm sure the vast majority of people who attend a protest won't have bad interactions with police, at a protest they're simply not there to look out for you, so it's better safe than sorry.