My understanding from Americans who have visited is there is no caving in Germany really. All caves are closed except by special permission from the government and a government official must accompany the group. My aquatences said the small community of german cavers were very excited as they rarely get to go caving, and used the Americans as an excuse to get the hard to obtain permit by claiming they were famous foreign cavers.
Tldr: if the scene hasn't changed, good luck being a caver in germany.