[Deduction]

Well if its scripted into the server to give the player weapons within the script.
Instead of:

pawn Code:

GivePlayerWeapon(playerid, weaponid, ammo);

Use:

pawn Code:

ServerWeapon(playerid, weaponid, ammo);

Parachutes don't count as cheat weapons, a golfstick is, so maybe OnPlayerExitVehicle use this:

pawn Code:

public OnPlayerExitVehicle(playerid, vehicleid)
{
    if(vehicleid == 457)
        {
        ResetPlayerWeaponsEx(playerid);
        }

    return 1;
}

Of course this will require another macro to restore all weapons.
So add in at the bottom of the script, this:

pawn Code:

ResetPlayerWeaponsEx(playerid)
{
ResetPlayerWeapons(playerid);
ServerWeapon(playerid, Weapons[playerid][Melee], 9999);
ServerWeapon(playerid, Weapons[playerid][Thrown], 9999);
ServerWeapon(playerid, Weapons[playerid][Pistols], 9999);
ServerWeapon(playerid, Weapons[playerid][Shotguns], 9999);
ServerWeapon(playerid, Weapons[playerid][SubMachine], 9999);
ServerWeapon(playerid, Weapons[playerid][Assault], 9999);
ServerWeapon(playerid, Weapons[playerid][Rifles], 9999);
ServerWeapon(playerid, Weapons[playerid][Heavy], 9999);
ServerWeapon(playerid, Weapons[playerid][Handheld], 9999);
return 1;
}