The amount of phone calls, text and mailers I get pretty much made the car sign invisible.

On the demand side, demographics are the big, invisible engine driving this machine.

You just mentioned one of the reasons why you want to remain invisible. 

It would make an interesting feature in a movie where the main character lived.And he could have a secret car that no one knows about...with a huge V8 from before the motor laws.All black and covered in special paint that could go invisible at the touch of a button on the dash.Well if you put it in movie besides building it, you can have my movie rights to the secret car idea (seriously).I'm serious, you might be able to sell this to Hollywood...and make more money--easier.But apartments already have amenities and in places like NYC there are shops below them--so it seems doable.Big numbers run though, full scale gym, etc...Just my 2 cents. 

Don’t forget the invisible victim.

The patch is invisible. 

I eventually cut the marble to fit so tightly that the seams were almost invisible and hid the drain below.

Because clip boards, hardhats and name badges make us invisible to the public.

MLS is the best place as @Joe Villeneuve mentioned and in the area I am in Vision Appraisal does a lot of the town property info stuff and their listings give some good info as well. 

Scammers need to be invisible to succeed, & tend to scamper like cockroaches if they get too much attention.I DO absolutely understand those who want to only give a red flag warning.