I don't get this instruction

I am making Cameron’s Cap for my son and I’m confused about this part of the instructions.

“Decrease section: Mark the stitch after each stitch marker with a safety pin. This will mark the center of each of the four double decreases. * Knit until one stitch before the marked stitch, dd; repeat from * around. Knit 1 round. Repeat these two rounds until 4 stitches remain.”

I don’t get the point of the safety pins. Will it not always be the stitch after the stitch marker? Why do I need the pins?

:??

I think you’ll have to remove the markers on the needles to do the double decrease. The pin goes in the actual stitch rather than around the needle.

So do I have to re-place the safety pins after each row?? Maybe it’ll make more sense once I get there.

I’ve never had to do it, but it is done on lace a lot. You might be able to eyeball as you go.