Re: Applying a Poly Sealant over Carnauba Wax?
At the end of the day.... a synthetic sealant is going to form a thin film (bonding to itself) across the car surfaces and bond to the previous protection layer(s). As to whether or not those bonds are strong or weak.... that all depends on the formula used and compatibility between the products that are expected to form a bond.
There is no law that states companies cannot market their products outside of the "wax over sealant" guideline. I am sure that some companies have developed their products to be durable if applied over a wax; and some are simply hawking their products for this type of application simply because "they can". Are they going to test their sealant product over every other wax product in the world? Of course not, that is not a "commercially reasonable" practice.
Technically speaking, the only way to prove the advertising is accurate enough for your taste is to perform DIY test(s). In short, they all leveraging ambiguity in the same way all other product manufacturers use the term "virtually" in their marketing (just one example). As all of us know, there are other terms out that that simply open the door to setting reasonable expectations and yet influence us enough to think the product will meet our expectations.
I mean, really, it is not as if the sealant layer will fall off the paint overnight if it is applied on top of a wax layer. While it can happen, it is not likely for many products. And where it does fall off that fast; then that is about the only time the advertising begins to toe the line between good and deceptive practices. To prove deceptive advertising, its just not easy most of the time.