A Stupid Question... OR NOT??

As people have said, there's a sense of psychology involved with colors. Manufacturers don't randomly choose the LEDs they place into their products. Red used to be the default because it was the cheapest and simplest to manufacture. With modern technology, all colors are available, so manufacturers can better consider why they use particular colors. There's a whole field of study devoted to color theory in marketing and ergonomics.

Green is closely associated with a sense of freedom and safety. It also represents stability. Green is synonomous with money and nature, two concepts that promote security and comfort. Hence, using a green LED lets users know that an appliance is fully operational and there's no cause for alarm.

Red is trickier. It does represent danger and obstruction, but it's also closely related to the concepts of passion and energy. Studies have shown that when placed among other colors of equal intensity, the human eye most often responds to red objects first. This gives red a sense of urgency, which makes it ideal for use with LEDs that denote trouble or demand a user's immediate attention.

A for blue, I believe it sees moderate use because intense greens and reds can be rather hard on the eyes, especially in low-light surroundings. Blues don't induce that level of stress. In fact, blue is most closely associated with a general sense of calm, which makes it a decent color when you don't want to overpower viewers.
I've noticed that when blue is used, it's generally in display features that are larger than the standard LED. We have a satellite box with several buttons that are housed in a larger, glowing, blue ring. It's nice to look at, and isn't as stressful as a red or green ring would be.

That should pretty much answer your stupid question, DeLorean.

(Oh sure, Encephalon closes the thread while I'm typing and fetching a sandwich. Well, anyhow, the answer is here.)

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