In theory this (which /is/ the Tesla idea) is not a broadcast system. It’s more like a waveguide and it’s more like a wire. The only energy you have to put it is the energy you take out. Plus the losses, plus pumping the standing waves.
A claim is that the idea is theoretically possible with the right conditions: my math and physics stopped at undergraduate level and I can’t analyze that claim.
A further claim is that it is possible to create the right conditions. Tesla didn’t succeed with that, and there doesn’t seem to be any published data supporting the contention.
I hesitate to call it a “scan”. There are people out there who make a good living proposing and developing unsuccessful ideas with somebody else’s money, but I don’t know that there is anything dishonest about it. Some people put money on a horse at 100:1. Is that a scam? Even given that long-odds horses are never fairly priced, is it a scam?