Unfortunately, if a buyer doesn't pay the fees, this can lead to the seller not sending the item and ripping off the buyer. If a buyer does pay the fees, then the buyer can say that they haven't received the item, they will then get the item and their money back. Thus ripping off the seller. Which method of paypal would you use being an honest seller?
There's another problem for the seller too. I don't know of any courier that will insure musical instruments that are not in hard cases (let me know if anyone does). For instance, sending a guitar can become a big problem for a seller. A hard case is needed, an extra insurance premium has to be be paid and perhaps paypal fees. This will put prices up substantially. In my experience, many buyers are not willing to pay the extra for a good service and want items sent the cheapest way often using idiots like Myhermes. I've seen buyers on BC complaining that delivery fees were too high and basically accusing the seller of ripping people off? Myhermes will deliver it for a fiver etc etc etc...
I'm at the point where I ask people to pay by bank transfer or paypal (as a gift) and arrange their own courier - they will only pay what it costs and so any problems with the courier are theirs and easier to sort out without a third party. If a buyer wants the cheapest postage solution then I state that I will not accept responsibility for loss or damage. The risk is theirs. Unfortunately, this method doesn't 'sound' too good to a buyer but at least I can be assured I'm not going to lose out.
It's a shame really as all it takes is a bit of honesty on both sides and if a problem does occur, to try and sort it out amicably...