Grumpydaddy

Kind of an ELI5, but I tune a radion into a specific frequency to listen to a station. If that frequency is constantly being modulated (changed), how is the radio not going in and out of tune? I expect it is finding a way to measure multiple frequencies around the tuned station and decodes the data from it's deviation from the tuned frequency?

I'm trying to understand what's happening in this circuit:

I------------------T1 (+333V)
I                 I
I                 R1(10K)
(pos)             I
1000V             I------------gnd (0V)
(neg)             I
I                 R2(10K)
I                 I
I                 IT2(-333V)
I                 I
I                 R3(10K)
I                 I
I-----------------IT3 (-666.7V)

I am learning basic DC theory from reading and sometimes I come across something I'd like to ask a question about, so:

1. In the above circuit, without the ground, the voltage across all components would begin at 10V and finish at 0V. By adding a ground, I'm basically saying "here is 0V" and everything gets redefined in reference to that point and I end up with a 10 volt circuit with +3.33 as it's highest voltage and -6.667 as it's lowest.

2. The electrons could care less, they still flow from the anode to the cathode of the battery under normal conditions, going from the highest potential to the lowest.

3. This example was only used to demonstrate voltage dividers. It revolved around worker protection present in aluminum processing. Each machine is in series and mobile grounds are used nearest the machine a worker is using. I assume that this allows the worker to have the least exposure to electrical shock as they are also at ground potential?

I actually think working though these questions has cleared everything up, but please, comment on anything I got wrong.

Also, sorry about the crappy drawing, the autowrap in this editor really made things tough to format

Thanks!