Comment by Father

Link removal requests can also be malicious. A blackhat seo will check his competitors domain to see if there's a spf record, if they're signing their mail, and if there's a catch-all (simply by checking if random mail is accepted). If there's neither they get a list of backlinks, from public web-crawls or sites like ahref, and request these links be taken down by sending mail with spoofed email addresses.