I'm usually a National customer but these are a few I remember from previous rentals:
Arkansas
XNA - No (Unsecured Lot)
Florida
FLL - Yes (Secured Lot)
MCO - Yes (Secured Lot)
MIA - Yes (Secured Lot)
TPA - Yes (Secured Lot)
Michigan
DTW - Yes (Secured Lot)
FNT - No (Unsecured Lot)
Minnesota
MSP - Yes (Secured Lot)
Missouri
BKG - No (Unsecured Lot)
Nevada
LAS - Yes (Secured Lot)
North Carolina
RDU - Yes (Secured Lot)
Virginia
DCA - Yes (Secured Lot)
IAD - Yes (Secured Lot)
RIC - No (Unsecured Lot)