Is it appropriate to hold my wineglass while a sommelier fills it?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
I recently went out with friends and noticed one person lightly touching the base of their wineglass while the sommelier was pouring. It caught my curiosity: Is this a part of normal wine etiquette?
—Michelle, Australia
Dear Michelle,
I chuckled when I read this, because I’ve done this same thing! But not because it’s proper etiquette. I just automatically put my paw on the base of the glass whenever I'm dining at a crowded table or in a tight space, because I'm afraid that my glass might accidentally get tipped over while the sommelier is pouring. Or if the server has to reach across the table to pour my glass, I might meet them halfway by holding my glass up for them (although at fancier restaurants especially, they might prefer we leave the glass on the table just to keep the number of moving parts to a minimum).
Ideally, a sommelier will pour your glass of wine without the bottle or decanter ever touching the wineglass, but accidents can and do happen, even to the most seasoned wine pros! However, as long as my glass has plenty of space and the somm has plenty of room to work, I’m less inclined to brace my glass for impact.
—Dr. Vinny