Yes, I can certainly understand how the logic follows from that. From a scientific perspective, though, I would say there's a slightly different view.
We know that things like gas contamination of an aquifer occurs in places, and the cause of that can actually be determined scientifically. For example, we know that the degradation of organic material like bacteria produces methane, and when that happens near the surface, it actually has a signature in isotopes, carbon-14. If you have ever heard of carbon dating, that's how it works. If the methane contains carbon-14, it had to have been created near the surface. It couldn't possibly have been generated by a deep burial, and you can actually determine—