Have you ever signed a "Harmony Letter" for an HOA?

A prospect reached out asking me if I could provide a review of their design and approve it in a Harmony letter. Their HOA requests that it's signed by a RA. I've never heard of this before. I don't mind reviewing and providing a response but is there any legal risk with this? Afterall, it's just a professional opinion, no?

Any one experienced with these?