Unfortunatly it isn't just seniors. We had a 30 something gal in my area who recently fell for a mystery shopper scam. They send you a bogus check, you deposit it and then go spend a percentage of it shopping. Once you done, you wire the balance remaining along with your shopping report back to them. They provide all the forms, reference letters, etc.
So long as they can snag a person once ina while for a few grand, they will keep on trying.