You got to be careful with the "signs" industry.
Most often, it's investors who bought the house for very little money, fixed it up, and are trying to sell it to you at the much higher price that is not supported by comparable sales, with possibly higher rate and points charged (because people without the credit history, or with bad credit history have very few options).
Otherwise, foreign nationals can buy without the credit score/social security, as an example - so it is true, when it comes to them.
Hope this helps,
Beachfront Realty, Inc.