Originally Posted by
AutoSlash
Why not just make a (non-prepaid) backup reservation at another company and call Silvercar when you land to confirm they have a car seat available? If they do, proceed as planned to Silvercar and cancel your backup reservation. If not, tell them you want to cancel and proceed to use your backup reservation. Problem solved.
I wouldn't cancel the other reservation until you're actually in the car and have an acceptable car seat.