Jcolespeedway, most cable vendors and certainly most in these forums and on this thread would have a hard time providing a valid and quantitative reason for the impact of dielectric value especially for the cable most likely to be elevated, i.e speaker cables. Now you expected them to provide technical explanations which would require quantitative analysis of not only the impact of flooring material on cable impedance, but what potential qualitative impact that would have on an audio signal. Keep in mind it would take literally minutes to measure real world impacts of carpet, wood, etc. on cable capacitance and impedance which already have questionable impact at all. if they can't provide measurements or have a qualitative discussion as opposed to hand waving you can pretty much assume they are guessing.
Similarly if someone cannot talk intelligently about RF attenuation versus frequency of a case opening then they again are guessing. Not to mention that the connected cables will absorb and communicate orders of magnitude more RF than a small opening.
Similarly if someone cannot talk intelligently about RF attenuation versus frequency of a case opening then they again are guessing. Not to mention that the connected cables will absorb and communicate orders of magnitude more RF than a small opening.