Guilt as Motivator
Direct Mail or Direct Response is one of the toughest sells in marketing, so these guys included a crisp $1 bill to entice me to fill out their 45 question survey all about household income, ethnicity, square footage of home, what kind of garage I'd rather have, etc. I can tell by the questions that there is either a lending institution, mortage company or home builder behind this survey. Maybe an association of all three.
Now I'm faced with, "Wow - they paid me already. I'll feel bad if I don't fill this out."