So it's been 8 years since thread239-391830: How reputable is it to use RF for wireless charging? but I'm involved in this topic and it piqued my interest while I was browsing. It seems like the conclusion to that thread was similar to a nonconstructive "proof" saying that either the company was lying/misleading with the power numbers and even if they weren't lying the power number would be above maximum permissible exposure from regulatory agencies (FCC).

So I did some reading on RF exposure safety trying to elucidate the statement made by VEBill:

"The science behind RF safety is sufficiently mature that one can calculate the radius of exclusion from various sources without needing to go digging into the journals to prove it all again."

But I'm struggling to actually understand said science. If the concern is dielectric heating, how can a Watt scale system produce heating that's actually concerning (aren't permissible exposure limits based on W/kg anyways)? I'm not talking about the regulatory hurdles involved in commercial realization of a system, I mean the actual health/safety concerns.

As in, when something like "The whole wireless power concept is deeply flawed. Because the gap between the practical and the safe is so small." is said, is "the safe" defined as allowed by the regulatory body? Please forgive me if I'm missing something; I would gladly appreciate some rough numbers/back of envelope calculation if I am. To me, I just don't understand how 1-10W of narrowband RF is relevant compared to the 1300 W/m^2 blackbody shining down from outside or even the 100W incandescent bulb. Is the concern that the unknown unknown of high spectral density is an issue?

Thanks