Yes, it is far easier and safer to integrate scales into the gate/docking station. No, it would not need to use lasers. The K.I.S.S principle always applies with aircraft procedures. Heavy duty truck scales should suffice. Obviously, these aircraft do not require extremely precise weight distribution measurements. Plus or minus 10% is likely good enough. This would also be far cheaper than retrofitting sensor systems into existing aircraft. The problem is, it shifts the cost from airlines to airports, and the airports will balk at the extra cost.