I learned recently that even Amazon is banning people for returns. My first thought was that they must have returned a ton of products, but after a quick "banned from amazon" search online it showed that many people with a return rate as low as 9% have been banned. Which doesn't seem like a lot especially if we're talking about clothing. Here's one example, but there's plenty more if you do a quick search:

http://cbs4indy.com/2016/03/21/amazon-bans-customer-for-retu...

Apparently the cut-off lies somewhere around 10%, they ban you for life though.

Plus most of us don't feel that returning five orders is more convenient than going to the store.

Is that typical behavior though? I have to imagine no. Personally I can hardly be bothered to return defective merchandise

Furniture is probably, next to a house and a car, among the most expensive things most people will purchase. And frankly I'm sure a lot of people just buy whatever guitar anyway, especially thinking back to the never-used one I used to have.

I think the key point here is that that set is probably small for most people and also differs from person to person. Someone else might insist on trying their keyboard but be happy to buy a bike online. And that's before we take into account people trying out goods in-store and then buying them online.