@tessarakt @benlockwood going rigid is also done, but police have a habit of "accidentally" breaking parts on the people who do that. Floppy is safer, although cops occasionally push holds until the person screams (... because otherwise how would they know they'd reached the limit of motion of the joint?)
The main point is that cops will *always* complain about protesters.
They complain when we set fire to buildings, they complain when we queue politely to talk to our MP.