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.

Stop worrying and get stream lining your business practices to fit your needs.I must admit I have one tenant that did not mention on his application that he has a invisible friend.

Low E coatings reflect invisible light range and heat.

I bet this apartment is all but invisible to them as of late.As far as it being a massive project, from what has been shown to me it doesn't seem incomprehensible to fix and rehab and set a price on it.

Have a lawyer look over the exclusions to make sure that you are not getting invisible protection.

How far away to look for comps is another conundrum; in my area you need to stay within a couple blocks, ideally on the same block, and not cross any invisible boundaries like major roadways, parks, train tracks, etc.

Low e does play a role in visible light.  

Keep in mind that my experiences, and thus this post, are biased towards what plays out in "Hot Market" SF Bay Area.Also keep in mind the NAR code of ethics implicitly assumes (clear as day... you just need to read the invisible ink between the lines) everyone has their own representation, just like our judicial system assumes each side in a criminal case has their own lawyer.