https://www.gamespot.com/articles/fortnites-51-update-fixes-ghost-peeking-but-create/1100-6460779/

Fortnite might currently be celebrating its first birthday with exuberantly large in-game cakes and additional challenges, but the jubilation was somewhat dampened by the issue of ghost peeking, which has been a troublesome exploit affecting the game's loot-loving, trigger-happy player base. The folks at Epic Games have been trying to fix it for months now, and had mixed results.

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