@7f73a7d1 I wasn't thinking of it as a "trick" so much as trying to understand what the legalities look like?
If, instead of a pendant, it were a big boom mic coming out of a backpack, would that be allowed?
(I 100% understand that Germany has very strong privacy laws, but don't have a good sense of how they intersect with the fact that everyone now carries a device with a hot mic all the time.)
@319bcfc8 The law I was referring to is paragraph 201 of the criminal code. It's fairly old and predates the GDPR. It roughly says that you're not allowed to record something spoken non-publically without authorization. It is very non-specific as to how that recording happens, or what authorization means. What would worry me about that pendant is that it makes it look like you tried to conceal the fact you're recording, implying an intent.
@319bcfc8 As far as I understand, a smartphone could also violate that law, if you used it like that pendant to record everything all the time. A big boom mic I imagine could be unproblematic under that particular paragraph of the criminal code as long as you're recording your own conversations and whoever is speaking to you is aware that it is recording.