I've gotten a couple of these - from Turkey, if I recall correctly, rather than India. The email asked specifically for a sponsorship letter and invitation. I think they asked to be uchi-deshi for 3 months or so. Since that isn't possible in our dojo and since I was a bit suspicious I responded with at bland note telling them we didn't have such a program but should they find themselves in Pittsburgh they were more than welcome to train with us. Never heard more. The next time I got one, I just didn't answer it.
So I can't sleep in the dojo?
Seriously though, this is an interesting type of scam. Well thought out, preys upon the general good nature of aikidoka, easy way to get into the country. Sheesh.