Just today I responded to a recruiter who directly emailed me "because my LinkedIn bio looked promising", asking: 1) How he got my email address, since it is not affiliated with my LinkedIn profile (uses my work email and only contains information about my current position) 2) That I wasn't interested, thanking him for his time

He responded, seemingly offended, that I "have a Gmail account, a very public account" that his "team of Search Engineers" found.