Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
"The wording of the MasterCard agreement seems to allow for coverage as long as you have partial paid rental (not entirely free)."
Suggest you check the current MasterCard rental coverage. There appears to have been some recent changes (not favorable to the cardholder), at least for the MasterCards issued by Barclays, Chase, and Citi.