I have never liked placing my trekking pole handles in the dirt or mud to get the pointy end of the pole into a grommet on a tarp or a tent. I prefer to have them up to keep them clean and safe from critters.
I found an "expansion bolt" at my local hardware store in the "National" small parts section - all those drawers of stuff. It's called out as a 1/4 x 5/8 Expansion Bolt, and is a rubber-like material with a nut embedded opposite the flange. It's similar to the locking device in adjustable poles, but has a top flange to keep it from falling in.
Since I installed EVA grips on my Gossamer Gear LightTrek™ 4s, I already have access to the top of the pole, and that made this solution easy. This part is a near perfect fit to the ID of the pole, and the flange evens out the pressure on the top edge.
To the left is the piece that normally caps the pole's hole. The hard part here will be not loosing the caps.
I'll leave the expansion bolts attached to the grommets, so at least I'll know where They are.