Hi Chris,
The body blocking at low power is the first thing everybody discovers! We all walk away from the airplane when doing a range check...most of us don't walk backwards for long distances) That also concerned me... until I tried full power. You'll note the blocking disappears at full output. Also think about a real world flight scenario.

How do we stand when flying. I'll bet you never fly facing away from your aircraft.. Nope you always are looking at and facing towards your airplane! The only other scenario I can think of might another pilot or person on the flight line walking or standing in front of you.. Not very likely of that happening without you reacting to clear your line of sight, even with a 72MHz radio.

Onboard volumes of fluids or heavy metal are thought to be potential problem, but a good real world human body free-range check will answer those questions for you.

Lee H. DeMary
AMA 36099