I had a car booked with this rate and went through a lot of umms, aahs, etc when picking the car up.

Seems this is an internal code used by Budget for Insurance claims. Apparently one's insurance company will make the reservation directly with Budget when they need a replacement vehicle while the insured's car is being repaired.

I was picking up at MIA and the woman immediately recognized the code as the MIA location is not supposed to be renting Insurance Claims; these are normally only rented from off-airport locations.

I was drilled for 5-10 minutes (How did I make the booking? Did I have my confirmation print-out from the web? {I did} Was I in an accident? Who was my insurance company? what was my claim number? Why did my insurance company reserve my a replacement car at an airport location?) In the end she did everything she could to have the system force the rate but she couldn't get past the screen asking for the Insurance Claim Number. She subsequently checked with her Manager who told her to do just do a new booking. When I compared the new booking rate to the X739200 rate, there was less than $5 difference. She booked the new car using BCD W852802. When reviewing the paperwork I noticed the price difference and she said she could refer back to the Mgr again and have him put a credit thru but I told her that was fine as my company would reimburse me anyway. I didn't want to draw any more attention to the situation for less than $5.

So, the long and short of it all based on my experience is to tread very lightly if trying to use BCD X739200 in the future.