I think like ANY other online store, if you are an MISB collector, contact them, ask for a higher grade of packaging, and be prepared to pay for it. Simple.
I laugh at people who spend mega dollars on toys, but then are surprised when cheap/free postage has dents in the box, we all know the postal system loves their impromptu soccer matches with packages, and losing shit under conveyor belts in big warehouses, where people will literally walk by it and leave it on the floor for months.
Postal Mafia wants your money, premium money just to get a very vanilla service, it's naive to think otherwise.