I don't think anymore, but in the last century there were several cases of therapists using hypnosis to unlock "repressed memories" of alien abductions. They usually wrote up books about it for profit.

Not specifically, but they will follow the absurd path of asking you leading questions until you convince yourself that you were abducted by aliens, and then being quacks will decide that their methodology couldn't be wrong, and so they validate your own invented beliefs no matter how stupid.

If it keeps you coming back for another session, they'll keep doing it, even if they know the whole process is bullshit.

This is thoroughly studied by psychologists. I feel obligated to tell you that multiple therapists have used access to repressed memories to control their patients. A large, highly organized religious movement overtly claims that its alien teachings are supported by repressed memories.