He was the chief organiser of the Internationale Essener Songtage [de] in September 1968 which showcased bands and musicians such as Amon Düül, Floh de Cologne, Guru Guru, Tangerine Dream, Franz Josef Degenhardt, The Fugs, Peter Brötzmann, Julie Felix, Julie Driscoll and Brian Auger and, for the first time in Germany, Frank Zappa.
In 1972 Kaiser and his girlfriend Gerlinde "Gille" Lettmann visited Timothy Leary in his Swiss exile, and under his influence became enthusiastic proponents of LSD use.
Kaiser continued to issue albums by Walter Wegmüller and Sergius Golowin, but got into trouble when he started releasing albums under the name of the Cosmic Jokers, a supergroup made up of artists who did not even realise they were participating in such a project: Kaiser had taken recordings of informal jams by various artists from the label and had released them under the Cosmic Jokers name without their knowledge.
As a result of this and negative press attention, Kaiser's contracts with his bands were voided by the German courts, thus spelling the end for the Cosmic Couriers label.
Because of the continuing appeal of the albums he released, Kaiser and Lettmann have regularly been the subject of journalistic investigations to trace their subsequent activities, all with very little success.