Setting server properties 'Hardcore' to 'true' does not ban players on death.

When I set the server properties to 'Hardcore=true', players can still respawn after death.

Players should obviously be forced to menu and banned from server.

Players can still respawn and die as much as they like.

Steps to Reproduce:
1. Create basic up to date Minecraft server.
2. Set server properties "Hardcore=true"
3. Run server.
4. Kill player or yourself and note the results.