I had a bad experience at the downtown Avis in SEA earlier this year. Apparently the 3 (a Barclaycard, Lloyds and Amex) cards I had offered for the security deposit were all "declining" and hence they refused to hand over a car. Cash and debit cards refused. All card companies confirmed no attempted transactions.

While stood in the office trying to sort, overheard conversations from staff about having no cars/being overbooked.
Ended up rebooking myself with Alamo - lo amd behold card worked first time.

Booked via Avios/IAG Loyalty (not BAH) and eventually got the cost difference refunded plus a very generous Avios recovery.