Car assigned is changed out?
 

I rent a full-size from a South Florida airport every week - usually Sunday to Friday and have been for the past year or so. Generally I get decent cars, but there's a lot of garbage too i.e Malibu's. Incidentally I use to get better cars during the high season.

Well I was renting one this Monday and I forgot to make the reservation. So when I landed Monday morning, I went on my laptop and made the car reservation.

When I went to collect my car 15 minutes later and attempted to drive off the lot, there was a problem with my credit card on file and I had to go to the Avis Preferred booth in the garage.

Here was my interaction:

Me: "I was told that there's a problem with my credit card"

Avis Agent: "What's the last name?"

Me: "Greycap7"

Avis Agent: "Are you still in the Infiniti? That shouldn't have happened, but I'll give it to you. I forgot to exchange out the car that the computer assigned to you."

Me: "Um okay"

Avis Agent: "I fixed your reservation, have a great day!"

Does this mean it's better to make the reservation last minute like I did, so the car I am assigned isn't exchanged out the last minute? To be honest, unlike airline and hotel loyalty, rental cars and Avis in particular doesn't really do anything for me. I'm pretty agnostic to renting cars as long as they are within my corporate policy.