Delphi Boolean Return Function Hint: Value assigned to '' never used?

Delphi Boolean Return Function Hint: Value assigned to '' never used?

I have
playerIds : Array[0..500] of string;
function isPlayerMob(check : string): boolean;
var
i : integer;
begin
for i := 0 to 500 do
begin
if ((playerIds[i] <> '') and (playerIds[i] = check)) then
begin
result := true;
end;
end;
result := false;
end;
I get the Warning
Hint: Value assigned to 'isPlayerMob' never used
Can somebody tell me how to fix this? The error is for the
result := true;