The green checkmark is solely assigned by the original question poster, and has no relation to voting - either on that answer, on the question, or anywhere else. The original poster may at any time assign, change, or revoke the green checkmark at his/her discretion.
You have an excellent memory. The question "Do live forex signal services work?" was closed as offtopic. For what it's worth, 5 members all "closed as primarily opinion-based" and more recently, it was deleted as there was no way to edit to salvage it.
This all occurs with no notice, and had nothing to do with your answer, just an off topic question.