Test Check?

Recently received a message from CashDuck stating that "test checks" are now required to verify user information before users can accept $ via an online payment channel, like Paypal. I've been accepting $ via Paypal since January with no hassles or problems.

Now I'm an amateur with GPT sites, but the test check costs $3 on CashDuck, and the survey offers that I complete pay out between $0.35-1.00, and roughly 3 out of every 10 surveys that I complete don't pay, period.

Does any GPT user out there know: What is the actual purpose behind a test check policy?

ANSWER: Re-read the "test check" page, and users can opt to pay $3 for a test check to expedite verification -OR- accumulate at least $20 in order to request a check by mail, which would also verify your address & allow you to receive payment via PayPal in the future.