I use mine quite a lot at Pontefract AGC as Pete has tried to stop erosion of the ground at the top of the shootingn lanes by letting in a lattice of plastic hexagons. Its working well to preserve the ground but you don't half know about it if you put a knee down on one corner or get your elbows on an edge of one.
The mat and the cushion come out because of that and elsewhere for inclement conditions.
Plenty have them and quite a lot use them. Best trick I've seen is to loop a long boot lace around the handles of a 3 section, 2 folds mat so that you can grab the laces, when its on the floor and it folds back up, whilst you pick it up. Then you can carry it over your shoulder using the laces.