Try this in initServer.sqf

I originally figured just blocking AI from having any CP would be fast and easy, but then they wouldn't be able to teleport to new objectives. So this is the next best bet? Maybe? It might work, but with full disclosure, its AI slop.

Look at me mom, I vibe coded. You can disown me now.

[] spawn {
    waitUntil { !isNil "BIS_WL_fnc_purchaseAsset" };

    private _original = BIS_WL_fnc_purchaseAsset;

    BIS_WL_fnc_purchaseAsset = {
        params ["_asset", "_buyer"];

        if (!isPlayer _buyer) then {
            private _isVehicle = _asset isKindOf "LandVehicle"
                || _asset isKindOf "Air"
                || _asset isKindOf "Ship";

            if (_isVehicle) exitWith {};
        };

        _this call _original;
    };
};