don't really want to open cases against sellers because often is not their fault they are lost in the postal system somewhere

I hope you are joking? It doesn't matter if it is one dollar or a thousand, if you don't receive the goods you should get a refund, the seller should do that without a dispute being opened but if they don't you should absolutely open it.

Not doing so will lead the seller to think they can get away with not sending things and even if it is only a dollar if 100 buyers all took your attitude that would be $100 in the seller's pocket at no cost to them!

If they are lost in the postal system then it is up to the seller to sort it out, find where the parcel is and make sure it is delivered or give you a refund.