[Deadsprout]

Because dry ice will melt and it can be made to look like the item inside has been stolen, but if you fill it with trash they're gonna open it and see a parcel full of crap. Hence why I can't see how people can get away with filling it with pellet

If the dry ice is not transported at the right temperature it will melt before being weighed in the distribution centers and no one will give you a refund because they will see that the weight of the parcel at the start was too low.

Yeah but the same must go for the parcel weighing correctly but being full of crap? Like who's going to refund a box full of crap lol, serious question how does this actually work??

my method worked for me.
coming back to you. I think dry ice is a bad idea. It would melt while still in the courier van. In that case you will end up in trouble with the shipping company because it is not allowed to transport liquids or material that could melt. The water would end up on other parcels and you would get in trouble because you should repay the company. You would then be reported by the company even before the goods arrive at their destination. Obviously with a dispute against the shipping company towards you, nobody would believe your story. Zero refund for you.