Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
And Budget's own website is pretty clear that a USAA membership card may be demanded by the renting location in order to get the USAA rate and benefits:
"Requirements for Renting
What is the USAA/Budget Customer Discount (BCD) Number?
USAA members should use Budget Customer Discount (BCD) number Y126500 (telephone) Y265001 (online) or Y126505 (mobile device) with each reservation to ensure maximum benefits are received.
To secure your rates, you may be asked to present your USAA affiliation card at the time of rental." (Bolding mine.)