Yes it is. Except my local shipping store is now charging $2 to print the label. No thanks, I'll just drive around with it in the truck until I get to a UPS Store.
FYI, you can always print the label yourself, now I know you're thinking the option isn't available sometimes, and well, that's because they make it very inconspicuous.
I prefer to print my own label and package up my own shit for return.
I suspect the reason for this more recent-ish option to have the shipper label and package is because:
1) When you generate the label at home, that has billed Amazon's shipping account, whether or not you return it - it's to try to the "print and keep" cases down, you drop it off, it's definitely coming back
2) I bet a lot of people don't use the same box/packaging (or one that's reasonably sized vs. the item) and wind up sending back a single cable in a box big enough to accomodate a microwave
So now, there has to be some auditing between the assumed cost of shipping vs. the actual cost for UPS (if the shipper packs it, it's more likely to be a more appropriately sized box/bag)
If I decide to return someone, it goes back, in fact, I actually print and package it up as soon I can print the label. And I almost always use the original packaging, or have so much on hand from other shipments I can get a good fit. I really don't like the idea of someone else packing up my return.