If you want the players to be warned that they didn't get the kill make sure than WarnPlayersNoKill is set to true.

AntiLootSteal 2.6
Adds a pickup delay to stop other players stealing the killers loot.
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Fix UUID error and Warns players that they didn't get the kill
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Bows now count as player damage
Fixed
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Most damage dealt option
Changing the option MostPlayerDamageWin to true will cause the person who dealt the most damage to get the players loot rather than the player who got the the last hit. This currently only works on mobs. You now also can use a %player in the configurable friend messages.
The above feature was requested by NmExHunTeRz. -
Fixed NPE
Just bug fixing.
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Wrong version
I uploaded a older version this one should work fine.
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Fixed no message bug
Should be fixed.
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Bug fix
There was a small bug whilst reading the config the plugin should work fine now.
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Factions update
This update now allows you to set it so the players faction members can take the items. Supports both FactionsUUID and the latest version of factions using Mcore.
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Recode and supports friends!
After having this up for a while I felt it needed to be rewrote. It supports all 1.8 and all the old features however now I have added the ability to allow players to add friends to take there loot (useful whilst pvping). The commands and other details are on the overview page.
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Monsters and Mob update
Delete your old config or back it up (for copying messages). This update allows selected worlds to have AntiLootSteal enabled(Big thanks to duper51& his server freakingfactions.com) . I have also added in selection to enable AntiLootSteal for mob drops (You can disable it in the config). I also have added an option to allow you to show or not show the message telling the player he/she has x amount of time to loot the items.