Curb Offers Only - Why?

[Pam R.]

So I found a duplex that I think is worth taking a look at. I e-mailed my realtor to setup an appointment to go inside, and he responded "I'll see what I can do. Listing agent says curb offers only."

Property photos show a cosmetically clean and functional place inside and out, no visible work needed (I know, the devil is in the details). It is priced well below current asking prices in the neighborhood - at least $20k - which immediately caught my eye and raised my curiosity. The ad says both units are rented (although the pictures are from empty units).

I know I could inspect after it's in contract, but I am more comfortable seeing the place before I even bid.

Can anyone advise on why a seller requests only curb offers? And what are your thoughts on this practice? Do you bid sight unseen?