The BoolValue won't change values.
Important facts:
-Filtering enabled: ON
-Type of script: Server script (Lives inside of the part)
-The script that made the BoolValue: Server Script (Child to ServerScriptService)
-Name of BoolValue: IsInMatch
-API Services: ON
-Part transparency: 1
-Part CanCollide: False (You can walk through the part)
Ask for any more info!
EDIT THE GAME HERE AND FIND THE PROBLEM: Edit the game
Script inside the part:
script.Parent.Touched:Connect(function(hit)
if hit.Parent:FindFirstChild("Humanoid") then
local player = game.Players:GetPlayerFromCharacter(hit.Parent) --If hit is player
player.IsInMatch.Value = false
elseif hit.Parent.Parent:FindFirstChild("Humanoid") then --If hat hits part
local player = game.Players:GetPlayerFromCharacter(hit.Parent.Parent)
player.IsInMatch.Value = false
end
end
The script that makes the boolValue:
game.Players.PlayerAdded:Connect(function(player)
local IsInMatch = Instance.new("BoolValue") -- Bool value to disable/enable
IsInMatch.Name = "IsInMatch"
IsInMatch.Parent = player
end)
Note: I deleted parts of the script which weren't related to the error.

7 comments
Probably you just need to use player:FindFirstChild("IsInMatch"). Is there any errors?
Yes, Here is the output:
Workspace.Platform.Script:9: ')' expected (to close '(' at line 1) near ''
Please accept my answer if that helped
It still doesn't work.
Try my edited one.
Try the new one.