Bikers aren't "portly", they're merely stocking up for the famine to come. Can't be too well prepared you know! Vest extenders for bikers originated when they wore their "colors" (vest or waistcoat with club emblem on the back)over a jacket and couldn't fasten it down to keep it from flapping. It does indeed have the function of making an out-grown vest fit, but I see guys buy a brand new vest and put extenders on it because it is so commonplace that the vest doesn't look right to them without the decorative chains attached. I don't know if this is relative to the Brian Boru jacket or not, but it's an interesting theory.

Jamie