Mentally ill people do it. Manic episodes in particular lead to lots of impulsive buying of things like plane tickets. Algorithms can target their ads at people with mental illnesses and exploit them while giving companies plausible deniability. Algorithms can even predict when a manic episode is coming on.

If they have enough data on a person, data brokers can easily classify people by mental illness and deliver their information to those looking to target people with specific conditions like dementia. Not nearly enough oversight or regulation on this stuff.