To the best of my knowledge, in 1/2" and below, a snap-ring on the anvil of your impact is pretty much the default position, as I've never seen anything else. It's also my preference. I just slap a new o-ring and snap-ring on my guns every 6-months or so at work, so they never get to the point where they're dropping sockets too easily.
Even my 3/4" impact has a snap-ring on it's snout.
The only pinned item I own is a 1/2" swivel made by Snap-On. I simply make sure to slip sockets onto it so that the hole isn't aligned with the pin. They stay on just fine, and don't require a punch or screwdriver tip to remove.