This has happened to me as well, but I just rejoined again (same server) and I was alive with all my gear.

This happens when you rejoin a server that is restarting. Once the server is fully "loaded" and ready to allow players to spawn, then you will spawn as "alive".

This also happens when you alt-tab out of the game.

I accidentally alt-tabbed out instead of pressing shift-tab to test it out and when I alt-tabbed back into the game (instantly, tabbed back) I was dead.