Passport required to join a fitness club

Just joined a fitness club and they want to see my passport, anmeldung and have my HR representative fill in and stamp a form. I don't even know if they have a stamp! What am I saying, of course they have stamp, we're in Germany.
I really don't see how it could possibly be any of their business, or why they would even give a rats ass as long as they get their money. That's how it is in the UK anyway.
I expect the authorities to want to see every little bit of paper down to my birth certificate but a gym FFS?

My wife, a German, says that's just how it is and people just accept it because that's how it's always been... Makes me want to do something subversive.

VIVA LA REVOLUTION!

rant over.

Probably your employer has a special deal with them, so you get lower rates. Of course they want to check if you are really an employee of this company.

This is why things like the GEZ, chuch tax, T-com SHIT service etc... will sadly never go away!

I feel your pain. Last time I rented a car, the lady asked "Haben Sie Ihr Anmeldung, Perso und Aufenthaltserlaubnis dabei?". Well of course I didn't have a perso, I just gave you my British passport! And much to her dismay, I don't carry around my Anmeldung nor did there exist an Aufenthaltserlaubnis for EU nationals.

If you don't have your Anmeldung, Aufenthaltserlaubnis, birth cert, your first born, etc with you, refuse to surrender them and/or talk to their supervisor

I think they want all that paperwork so they can track you down if you try to get out of your contract/ stop the DD etc...