What it is
Margin pole is not the same as a waggler down the side. You are shipping two or three sections into a foot or two of water, with elastic that can stop a double-figure carp before it reaches the reeds. Paste, meat, corn and worm all catch. Plumbing the shelf is the whole job.
The mistake is treating the edge as an all-day line. Keep it quiet, feed it late, and have the net in the water before you hook one. A 4 elastic and a 12lb carp at two yards is how people lose the fish of the day and then blame the method.