HelloCustomerans welcome to justanswer.com,
The dealership is right in the fact that the wetness you see wont let all the fluid drain out. I see a lot of these models with the same issue.
But as long as you have an extended warranty that you are sure covers this part then why not have it replaced? I am sure you can take it to any repair shop that accepts the warranty and have it replaced minus your deductible.
What would cause this leak and what parts would need to be replaced. Would the color of the fluid uncover any other possible problems?