I don't know about quail, but I tried this method with some roosters a couple of years ago. It didn't work well at all for me.
I put the big plump rascals into a bright orange cone, that I had bought at Home Depot just for that purpose. I held the cone with the rooster head sticking out the bottom and the man used the loppers to cut off the head. The problem was the loppers wouldn't cut the feathers no matter how hard you pumped em. We ended up laying the cone on the ground next to a 2x4 and using the old tried and true hatchet method.
I also tried to kill a banty rooster with a spade a few years back with great un-successfullness. He just showed up here one day without any invitation and I tolerated him as long as I could. The little b@$t@rd roosted on the balcony outside my bedroom window every nite and crowed the most hideous, raspy, annoying noise and kept me awake. I caught him one day and held his feet and laid him down on the ground. My friend put the spade down on his neck and stepped on it. Thinking he was dead, I carried him to the compost pile and thru him in. When I was reaching for the shovel to cover him up, the sneaky little b@$t@rd jumped up and ran off.
The spade had slid sideways off the feathers on his neck and all he got was a small cut and a couple of lost feathers. Fortunately for him, my friend took a likin to him and took him home with her. He now has several girlfriends his own size and has been able to make lots of baby chix.