You can publish four machine-readable 'do not train on me' signals and still have no enforceable preference.
RSL, IETF AIPREF, W3C TDMRep, and IPTC all let you say 'do not train on me.' The tokens do not match, the attachment surfaces do not overlap, no rule says which wins when they disagree, and no major model developer has committed to honoring any of them.