t's more of a safety issue than anything else. when you're wiring your car amp to your battery, you put the fuse as close as possible to the battery, right? that way, if a short should occur in the system, the fuse will prevent the car from igniting.

This puzzlement visited me in part because I've made some minor changes to my new car and it has a number of "switched ground" systems, mostly lights. All other truths about + fusing still apply. First time I'd ever encountered such a thing.

it draws the same amount of current whether a load is present or not.

Look for me next week on America's Most Wanted. I can see about 12-15 of those darned spud transformers (plugged in) from where I sit -- many of them serving stuff that is switched off!