I noticed that when I changed my oil; there is no magnetic drain plug fitted as standard. These are cheap to buy thouigh and are seen for sale on ebay. Next oil change I will fit one. Its normal for a bit of metalic debris to accumulate so it wise to have one. I used to flush my engines each time using deisel (yes deisel, right up to the dipstick level) its cheap and works well, some folks even run the engine for 20 seconds or so. But - the danger of flushing is that it spreads the thick gunge in the bottom of the pan with its melalic debris all over the big-ends etc - Ouch - could be a bad move? I reckon no need to flush with regular changes at 10K miles, especially when done from the bottom.
Steve