Is there any advantage (or disadvantage) to addressing that fact in the letter or is it better to send the letter as an anonymous investor who happens to be a neighbor?

Maybe I'm off base, but I always feel kinda bad for a seller who thinks that calling the number on an anonymous sign in a vacant lot next to the Dairy Queen or responding to a "handwritten" yellow letter is a good idea.

You could also make it optional, a visible and anonymous vote.

If this wasn't the case it would defeat the purpose of being anonymous.

I just don't think anonymous adults should be giving advice directly to children.

Establish a corporation with anonymity in WY or NV.  

Mostly it’ll provide some anonymity.

Delete your Bigger Pockets account and open a new one with the name "A. Nonymous

I also suggest a drive-by so they are not unpleasantly surprised by the neighborhood when they get to the showing and just keep on driving by anonymously as I wait outside.

Make sure you find one that activly Invests in Real EstateCheck out the Central Florida REIA cfri.netI am currently pursuing:Title in Land Trust (Anonymity) helps with Probate so my heirs (spouse, children) can obtain the propertiesBeneficiary of Trust is the LLC (Some legal protection)Umbrella Policy for Protection not coveredDisclaimer: This is a suggestion of what I am planning to do, not advice on what you should do.