If you're entering the EU or a Schengen-signatory, even for a transit flight, you are required to pass through security (all passengers on any flight departing within the EU must have passed through EU-legislated security, to avoid the case where their incoming security has been lax). Some places include more (the UK requires security for /all/ passengers arrival on an international flight, regardless of the EU).
What one doesn't have to do is pass through border control or customs (unless one is transferring onto a domestic flight, then quite where you clear border control and customs varies from place to place — in the UK you clear the border at the port of entry and customs upon arrival at your final destination).
Also — just to note, I can't imagine anyone ever being actually arrested under the no-right-to-silence clause (and if they did, I expect it'd just get take to the ECHR and thrown out) except potentially for UK citizens/subjects/nationals/whatever-other-categories-there-are-that-I-always-forget (for whom entry cannot be refused).
If what you mean by not being sure how it works for transit is how it works in the US — you must posses a valid visa (probably a transit visa) or not need a visa (VWP, citizenship, etc.) for entry into the US, regardless of your further destination. Sadly, for many of us from Europe, many flights to South America require pre-approval from the US, because you cross US airspace, even though you never land.
What one doesn't have to do is pass through border control or customs (unless one is transferring onto a domestic flight, then quite where you clear border control and customs varies from place to place — in the UK you clear the border at the port of entry and customs upon arrival at your final destination).
Also — just to note, I can't imagine anyone ever being actually arrested under the no-right-to-silence clause (and if they did, I expect it'd just get take to the ECHR and thrown out) except potentially for UK citizens/subjects/nationals/whatever-other-categories-there-are-that-I-always-forget (for whom entry cannot be refused).
If what you mean by not being sure how it works for transit is how it works in the US — you must posses a valid visa (probably a transit visa) or not need a visa (VWP, citizenship, etc.) for entry into the US, regardless of your further destination. Sadly, for many of us from Europe, many flights to South America require pre-approval from the US, because you cross US airspace, even though you never land.