Question 1:

Other than flying from Canada where there is a carry-on baggage restriction (no-carry on) there are no restrictions on electronics of any kind, domestic & international. If the items that you carry are not on any prohibited list then there is no valid reason why they cannot be carried aboard once they fit within the carry-on baggage limits.

Question 2
You kind of answered your question with the first line
"what can I do to insure its safety" - insurance. Once something is out of your sight you can't predict what will happen to it. So you pack it up well, insure it and hope it arrives in once piece. The only other option you have if you are sure you do not want to carry it aboard or check it would be to fedex/ups it ahead of time.

However I have a piece of advice. I travel quite a bit with radio equipment. I manage to carry it all in one carry-on (actually a well padded camera bag). To make things easier for the screener I pull out the major items and separate them in a tray, much like you would for a laptop. This presents an easier scenario for the screener. Now they are not dealing with cables on top of cables on top of a dense electronic component. This prevents the 'x-ray' lighting up scenario you mention. Pre-empt and prepare.

I'm travelling ORK-EDI tomorrow and GLA-AMS-SEA-YVR at the weekend and am travelling with radio equipment, we'll see how it goes. I had no problem on the outward leg but obviously things have changed a bit.