[WMarshal]

It is not theft if 3 conditions exist: 1) someone broadcasts energy that they themselves are not recapturing and would otherwise be lost, 2) usage of the energy by the person that captures it does not diminish the ability of others to utilize that energy as intended, such as listen to a radio broadcast, and 3) The person capturing the energy does not have to commit trespass or alter another's property to do so. If these conditions are met, it is not theft.

[bvw]

What other personal inventions of excuses will you throw up?

The power drained by these devices from a broadcast power field is diminishing the strength of that broadcast for those in the shadow of those devices, just as a building shadows the broadcast of light from the sun. Subconsciously you are aware of that effect because benefiting from a building’s shadow is an example you gave.

To have the same reach in the presence of such parasitic devices, a signal transmitter would have to amp up its signal. That’s a cost, your parasitic device costs someone else to power it. Theft.

When you stand in the shadow of a building protected from the heat of the sun, you are not costing the building owner anything, he still would have to dissipate the heat of the sun. The sun’s power is free to all. It is similar to using the waste heat of the AC unit. Use all you want!