Sorry if I don't know much about how car rentals work, I'm a rookie for sure. OK, that explains it about Hotwire not being prepaid and why I could choose Enterprise by name. So, do you think it's all right to trust the Hotwire confirmation about the Enterprise car, even though Enterprise itself gave me a "no availability" for the same time, place and car when I tried to book it directly? It seems likely that Hotwire will make the reservation and let the customer repent at leisure when standing at the counter with no car in sight. To recap, using the board's support links, I attempted to book a compact car with Enterprise for Sept. 3 - 9, 2009 from SJU. Told it was not available. I went through Hotwire, which gave me retail options, chose Enterprise and received a confirmation for a compact car Sept. 3 - 9, 2009 from SJU. Would you trust Hotwire to make Enterprise deliver? We're only talking about a $7 savings over my Thrifty confirmation. And is there any downside to keeping both confirmations until I'm actually standing in the San Juan airport trying to pick one up? No money has changed hands and no credit card numbers were taken, yet. Do I post this as a Hotwire "win" under rental cars? Thanks for sharing all your invaluable experience and assistance!