We have doors on both sides of our 5er and use mats (almost) all the time. If we are truly stepping down on grass, we don't use mats. But if stepping down on gravel or dirt, almost always do.
Our situation for doors on both sides are handled, as you can see in the photos below. We don't use any kind of stakes or anchors, we just simply put heavy objects on top of the mats. The corners may blow up sometimes, and sometimes in the morning, they are blown over, but never blown "away".
This week-end we are at Mississawana State Recreation in Indiana and the weather is about as perfect as it can get. No high winds predicted or anything. So, the mats are not held down right now, except with the door steps.
Back Side: Mat held in place by the door steps. If windy, I'll place rocks or logs on the corners to hold them down. Doesn't matter, dirt or concrete, they are never staked down.
This is the campsite we are at right now at the moment:
Front side of the camper. This week-end is an exception. We have great shade, so I left the picnic tables in the grass. Normally, the picnic table is on one of the mats to hold it down.
This was last week-end, same campground, different spot. Door steps hold one mat, picnic table holds the other. They don't blow away!
We've been to only one private campground that did not permits mats in all our years of camping. I suppose that's because we do almost exclusively State Parks with an occasional overnight at KOA's or Good Sam parks.