The bar you must jump to be able to do this to some one is state law, and differs by state. The bar in Bavara is, arguably, lower than in some other states by my (uneducated in the laws, so not very relevant) reading.
For example in many German states, it requires a crime to be imminent. In Bavaria this is not the case.
> They were known activists
Does "activist" hear mean they'd previously engaged in illegal activity, i.e. blocking roadways or similar "protests"?
I don't know if there was concrete evidence of past crimes/actions for them. By my reading, Bavarian state law does not require this. In some other States, it is listed as one of the conditions to meet or "likely to repeat" is somehow baked into the lingo.
One would think that people gluing themselves to things is a self limiting problem.
https://www.zeit.de/gesellschaft/zeitgeschehen/2023-09/letzt...
> Zehn von ihnen waren laut Münchner Polizei während einer Blockade am Freitag in Gewahrsam genommen worden.
Also, courts seem to perform some checks, there are reported cases where even repeat offenders were let go:
https://www.br.de/nachrichten/bayern/vorbeugender-freiheitse...
> So entschied zum Beispiel das Landgericht Landshut, dass ein rund sechstägiger Präventiv-Freiheitsentzug für Klima-Aktivisten unzulässig sei, die sich 2021 auf Autobahnbrücken rund um die Internationale Automobilausstellung (IAA) in München ein paar Meter abgeseilt hatten, worauf die Polizei den Verkehr stoppte. Kernargument: Eine Wiederholungsgefahr sei nicht hinreichend erkennbar.
And there are several records of perpetrators announcing followup crimes right after having been judged. Some were even committing their next crime within a few hours: https://www.merkur.de/deutschland/kleber-aktivisten-letzte-g...