There have been plenty of threads about buyers purchasing an item that is collection only and ultimately changing their mind upon inspection. Some simply don't provide the collection code and force a refund. It may be frustrating for the seller, but it is ultimately better than sorting out a partial refund or a return at a later date. There just has to be some common sense.

   With regards to exchanging details before purchase, it used to be about fee avoidance, but lately there were also instances of sellers having to deal with aggressive buyers turning up at peoples home (price haggling, not taking no for an answer, etc). Member safety became an issue and it also generated a lot of mainstream (negative) publicity.