No charge for shipping or the return either (you contact FedEx and they send the return packaging and can pick it up as well).
Motorola knows people will attempt to scam them for phones with this, if you read the FAQ for this Try Before You Buy offer they make it clear they can and will remotely brick the phones if you attempt to rip 'em off (not sure there's any actual way to stop that, even with using custom ROMs, etc, I have no idea).
If you do decide to keep one they'll attempt to charge the credit card the full price, and if that doesn't go through they'll then push lawyers on you so, I'm pretty sure they're covered.
Worse comes to worse they can simply push the IMEI to the national blacklist and the phone is dead regardless.
I mean, for a penny, if they're willing to ship me one I'd love to try one out for a time, can just slide my T-Mobile SIM in it and I'm good to go.
<least till this Sprint/T-Mobile and now SoftBank crap gets resolved 'cause if it happens you can be damned sure they're going to kill the $30/month plan so many of us love...>