But in Germany, the section of the copyright law concerning data mining specifically says that scraping websites is legal unless the owner of the website objects in a machine-readable form. robots.txt very clearly fulfils this standard. If any bot owner complains that you labelled them as a bot as outlined above, they would be admitting that they willfully ignored your robots.txt, and that appears to me to make them civilly liable for copyright infringement.
Source: https://www.gesetze-im-internet.de/urhg/__44b.html
I also had a look if these actions would count as self-defense against computer espionage under the criminal code, but the relevant section only outlaws gaining access to data not intended for oneself which is "specifically protected against unauthorized access". I don't think this claim will fly for a public website.
https://www.bakerdonelson.com/return-of-the-rocket-docket-ne...