I've been going through the archetypes to both add flavor and provide detail for players not familiar with the game and while doing so I came across this thread because I was also a bit confounded. I had decided to skip it for now but when I was proofreading my description of the force shield belt I did a double take on the fact that force field effect is noticeable by default which inspired me to add the last paragraph:
"You possess a high-tech, futuristic or super-scientific shield generator which allows you to surround yourself with a protective screen (similar to the Force Field power) and which grants you a +10 bonus to Toughness and immunity to any effect with a Damage rank of 5 or less. You can raise or lower the shield as a free action.
The force screen produced by your shield belt is noticeable and produces a visual distortion (or some other display) as well as a distinctive sound while it is active.
Your shield belt features controls which allow fine-tuning of the force screen it produces. This means you could potentially alter the visual or auditory side effects produced by the force screen to convey simple messages such as a warning or request for aid."