The ad for Rain Shield, as I pointed out earlier, is filled full of snake-oil claims and statements. Generally when a product is advertised with dubious claims, it is usually not what it claims to be. Especially when it also appears to be overpriced, which at $26 per aerosol can, this one certainly is. So don't blame anyone here for doubting the product, as it has all of the classic signs of snake oil.
It is also funny when a person advocating the product makes a statement that their 36" dish with Rain Shield treatment doesn't have as many rain fades as their neighbors, with their untreated 18"-20" dishes.
Seriously, how much less rain would be on my Dish if I used Rain Shield vs if I used a good quality car wax? Or Rain-X on the dish and Armorall on the LNB. The difference in terms of picking up a signal or not would have to be extremely small. For one thing, there is no evidence that any of these actually make a difference, so the differences between the different treatments is likely to be far smaller yet.
Another one of these super repellent products is WX2100, which sells for $30 for an 11 ounce can. It claims that it not only works, but it works for 10 years!