It all about the side chains with silicone-based polymers. One silicone polymer may have a flourocarbon sidechain and not be soluble in water or other non-harmful solvents. Another polymer with the same exact backbone may have a methyl or ethyl side chain and be perfectly soluble in water.
Most of the later silicone based polymers have a hydrophobic and hydrophilic side and will cause an emulsion in their solution. It is the job of the chemist or chemical engineer to ensure that the polymer is safe on the desired surface and interacts favorably with solvents that are safe on the desired surface. Everyone on here knows that water doesn't hurt much of anything in moderation so the chemist will design the polymer to be water soluble and still safe when cross linked across a given surface be it paint, vinyl, leather, plastic etc.
It is my assumption that the chemical companies such as pinnacle, meguiars, four star, ultima and lexol have done their research and know exactly how their product will interact with a surface. They design their product to protect and condition the surface and clearly state what surface it is they have designed their product around. IMO if a product say "leather and vinyl protectant" it can be safely used on leather and vinyl. Same goes for tire and trim; rubber and plastic, plastic and glass, paint, all interior etc.
