HTC Incredible :: How Does Pre-ordering Affect 30 Day Return Window?

Verizon's normal return policy is 30 days from date of purchase. Say you pre-ordered the Incredible online on April 19. Does that mean you have 30 days from April 19 to return the phone, or 30 days from the date it was shipped, or 30 days from the date you received it? Anybody know? Also, does Verizon actually have to have received the phone within 30 days for it to count as a valid return, or do you merely have to have shipped it back to Verizon within 30 days (and perhaps they receive it 31 or 32 days after purchase)?