I don't cut plugs at all anymore. I can pinpoint dead on and have never used a handheld pinpointer ever.
I carry a really big screwdriver and pop up any shallow finds.
If it's deep, I cut a straight slit and lift up the grass on either side of the slit. Then I pry up the soil always to the very edge of hole as to not scratch the target.
When I'm done, I put all the soil back and push the grass back to normal. You will never tell I dug there and the grass does not die.
I do carry a small shovel out relic hunting but still use the screwdriver for 90 percent of my targets even in plowed fields and bushes.
It's more intimate as I can see non-metal objects in my hole like arrow heads or beads because I'm going slower and only prying up a little at a time.
This method also gives the back much needed rest as it's a good stretch when you kneel over the hole.
I do not kill tree roots either and the screwdriver works good to get around them. Why should I hurt trees for my own selfish gain?
When the ground is rock hard, the only thing that penetrates is a screwdriver.
The only place I don't use it is at the beach but otherwise, it's my main tool.
Cheers,
Dave.