Neither are the manufacturers. I'm very sceptical;
- This technology hasn't been around long enough to be field proven for even ten years.
- There's likely to be some small print get-out clauses.
- What's the chances the supplier or manufacturer or agent will be around for comment in 25 years?
- What's the chances the original customer will have proof of purchase in 25 yrs from now?
- What's the chances you as an installer will have an invoice for your purchase in 25 yrs time?
This sounds like a sales gimmick to me. Just make sure you don't come short because of it. I would stipulate on the invoice that any materials warranties are only at the discression of the agent or manufacturers and keep yourself out of the loop if you can. I would read up on consumer law in your location and make sure you're not liable by that route as well.