That was awfully considerate of him given that his old boxer motor will probably outlast most of us. Just think of how many unnecessary spinouts and lowsides he's preventing!
Phil's right, that old airhead will last forever. I was once told by a BMW mechanic that BMW had three terms for oil loss, weepage, seepage, and leakage. The first two were considered normal.
BMW (Bad Mans Wheels)... my guess would be that's actually a terrorists machine ... what you assume is an oil-rag ... is actually his prayer mat cooling in the shade