Water will bead on the paintwork when it's brand new and will take a few weeks for that effect to wear off and even then it's not really a very good test.
I would ask for the money off the car instead, even though i think these products are okay if applied correctly they cost the dealer next to nothing.
That's a key point. If you visit any of the detailing forums you will discover that detailing is an obsession for some and an art-form for others. My question would be how well trained the employees are who get assigned to apply this product and their attention to detail. And the question that was asked originally which is whether it was applied in the first place, or was it a half-job if they're doing it for free.
If washing, prepping then waxing a car takes as long as three hours (for me at least), then it's interesting to see how much time they spend applying these chemicals and whether they do any prep to the car beforehand - I can't imagine 3 hours of labour comes cheap in a dealership.
If the prep is poor, then they're effectively sealing in contaminants that are on the car. Contaminants such as brake dust, oil, traffic film, etc, etc will most definitely be on your car when it arrives. And once it's sealed in there, it's pretty much there for good, as I understand that this sealant stuff can't be removed easily.
But hey, some aren't bothered about that and will never think twice about it. But if you're like me and you're the sort who won't let a machine or anyone else wash your car because you don't think it'll be done properly, then you'll want to think twice about whether you can trust them to do the job.