Are you serious? I walk up to a glowing green curtain and suddenly, without any warning, I go from full health to dead and have to trek all the way back 1/4 of the way across the map to get my stuff?
That’s an absurd design decision from the early-2000s when no one knew any better. That’s the exact same sort of mechanic from the early days of Everquest 2 where you could just randomly die while crafting. That’s just an ABYSMAL design decision.
This is fundamental Game Design 101. You don’t put mechanics into a game that arbitrarily kill a PC without any kind of warning or messaging. And no, the fact that there’s a green light isn’t a warning. There are other places in the game that you’re supposed to interact with that glow, some of them being green. For all the player knows, it’s just a magical curtain that’s going to teleport them somewhere, or the entry to another area, or the entry for a dungeon.
If you’re hell-bent on killing a character to keep them inside a boundary or keep them away from areas you haven’t built/released yet (a ridiculously poor choice if you do it, but whatever), you should give the player a countdown that forces them to turn back and then if they don’t, sure, go ahead and kill them.