Depends. When millions are on the line between companies, people are surprisingly willing to take a hand-created excel file as 'proof'. For example: https://financialpost.com/pmn/business-pmn/tricolors-excel-g...

Feels like this is likely to be targeting government and major corporate clients, in which case they're probably in a strong place to negotiate agreements based on charge reported by the drone's on board software. Not to mention the utility companies themselves, who are mentioned as the initial market.

What's unviable about having the power company vet the thing that reports "I drew X joules from line Y" like they would vet any other meter?

B2B transactions like this are handled fine with contracts and lawyers all the time, I doubt it would be an issue. In the worst case, the utility could own the recharging module on the drone, just like they own your power meter.

Unmetered electric service based on "trust me bro" is actually the default (at least in the US) for a huge variety of devices, like streetlights, cell towers mounted to electric poles, public irrigation systems, etc etc.

Almost every US utility has a "UM" process to self-assess an unmetered load's consumption and be billed. So, yes, it's not only viable but widespread.

I mean, if I have to pay them by how much power I draw, I'm pretty glad they have a way to measure that, because I don't.

What's there alternative in this case? If I can land a drone on the power line and suck up some power, they can either charge me when I tell them I did it, or they can not charge me.