It's gets pretty windy where I often camp and it has caused equipment damage before.

My friend uses the blue and/or silver heavy duty tarps at camp and in high winds, the grommets rip out. I have used the pebble approach on his same tarp and the winds didn't damage the tarps further.

My conclusion is the pebble or whatever in the tarp has been more reliable and flexible than grommets, just not as convenient. When I use the grommets in wind, I will sometimes use a loop of bungee cord ala the USMC tarp. That gives some give to hopefully reduce damage.

But with a space blanket, the weak part is the blanket itself. And the wrapped pebble or grasses or whatever you put in there approach would probably be the strongest way to do it. My disclaimer is that while I have used tarps a lot in high wind, I have never tried a survival blanket in high wind.

I have seen tarp setups survive where the EZ Up type canopies have had their frames twisted and broken by the wind.