Atul, Hello! 
You make really good points here. I also think that when it comes to SEO, or other content related changes that you make to a website, the fallout needs to be considered.
I wonder, with more customers willing to go a little further to buy, or dealers willing to ship cars a little further for a sale, do we have to lock down the GEO?
When I see users come in from a zip code that might not be close by, first I think of "brand awareness", then I think of social/display retargeting. They are in the "pool" and will get served for a specific amount of time. Maybe they come back, maybe they do not, but now they know the brand. Will they remember? That remains unknown and could be considered wasted dollars.
The stuffing of GEO's is really a concern, we have all seen that. I wonder about mocking the homepage design structure, which I am going to think about a little more before deciding if that makes sense.
All in all, nice to see you here. Hopefully you'll be back to spread more data nuggets for all of us
