Ideally, this is in answer to a TLP post that actually asked "Do We Have This One?". Otherwise, it's answering a question that hasn't been asked, which looks odd.
Using the message should be followed by a link to the trope page and an explanation of why they are the same to avoid misunderstanding, and to allow informed discussion if there is disagreement with the assessment.
Please don't post only the trope name, as doing so can lead to confusion on the part of the reader.
Should a TLP come under scrutiny as being a preexisting trope, any citation of said trope should be made only with the consideration of whether examples existing within the TLP would actually be accepted within the boundaries of said trope. Neglecting this could result in the examples being removed by those who do not agree they meet the criteria.
Any further efforts should await response by the TLP creator or custodian. If they don't respond within a reasonable period of time then the other tropers on TLP can take the appropriate actions.