Seat Plug Issues

I use that carpet stuff inside the hull and on the ground.
Inside the hull it does keep stuff from sliding around.
I take the stuff from the hull, fold it twice, and use it on the ground when I am loading my kayak using the Yakima easy loaders.
I put one end of the kayak on the pad and it keeps it from sliding on the ground when I am lifting the other end.
Keeps it from getting gouged up too.
I have an '07Revo. Straight seat plugs.
After I put my seat in I take the heel of my palm and push down on each peg making sure it seats properly.I get a very snug fit this way and don't have any problems with the seat sliding out.
I also use the back holes.

Banjotad

I have an outback with the same style adjustable seat pegs as in your picture and have had no problem with them popping out.  When I had the original non-adjustable ones it was a nightmare keeping the seat intact. 

Frank

The adjustable plug mod seems to have solved the problem for me and my Revo too.