Diablo III in Hardcore mode is a harrowing experience. No matter how good you are as a player, there's always the real worry that one careless move will mean the end of a character you've worked hard to level. Unfortunately, sometimes that careless move is simply playing in a public game, as griefers have been exploiting the votekick system to cause players to die and lose everything through no fault of their own.
As it currently stands, a player who has been kicked by popular vote will be rooted in place for 10 seconds while the character is ejected. Griefers have used this to kick players in the middle of monster-heavy rooms, resulting in 10 seconds of uninterrupted monster beatdowns with no chance of reprieve.
So how to fix this? Well, Blizzard plans to remove the 10 second lockout in the near future to ensure that a kicked player can still move and respond rather than get pointlessly murdered. There's no word on whether this will be a hotfix or rolled into a larger patch, but it's definitely on the horizon. Until it goes live, though, you might not want to have your hardcore characters on a public game.