0. Never take your primary personal or work cell phone to any demonstration
1. Cover your face, if you can, or wear anti-facial recognition makeup
2. Do not use social media from primary personal devices
3. Anyone intent on trying to join the cause is a cop. Until proven otherwise, anyone you meet is a cop
4. The standard response to any official questions in the future is to deny all allegations, keep quiet, and ask for a lawyer
[0] https://www.legifrance.gouv.fr/loda/article_lc/LEGIARTI00002...
Cops/Feds can do parallel construction to nail you anyway. Use the fancy technology to discover what happened, build the case backwards with old fashioned techniques.
They never have to reveal the advantages they have, it's rigged.
5. record your interactions with anyone around you, specially cops
The number 0 point (not bringing your cell phone) makes it pretty difficult, so you need an everyday phone, and a dedicated "demonstration" phone.
And presumably did not arrest him on exit!
But I'm afraid since Brexit the UK gov has fallen over itself backwards to look like it's still able to work with EU agencies. It's more valuable to them to overzealously agree than to resist when we had a secure table at the EU table.
What are the tangible pro's and con's of Brexit?
IIRC, EU membership forced Scandinavian countries to broadly weaken regulations on toxic substances and discard the precautionary principle.
Would UK on Euro subsidize worse economic performance of other nations?
What is the new, actual situation in N Ireland in terms of trade, regulations, and standards?