I might add many posters would or will say I leave a positive feedback and then mark down postage stars !!!!!!!!!!
So, what is the cumulative effect?

The seller is getting anonymous subliminal prompts to ........decrease postage...........................decrease postage...........................decrease postage...................
........decrease postage...................

so the seller does and increases the product price, that increases ebays fvf% and the knock on reduces the sellers profit margin so the seller realizes they need to offer the product at a greater price to maintain margin.

So the cumulative effect is increased prices to the consumer

..... the consumer asked for it .... anonymously..... and got what they asked for............. increased prices.

The reporting of postage piracy appears to me to be a self serving ebay process to maximize profit while, at face value appears to be to the customers/buyers benefit