Upload & Sell: On
I have done this many times, providing the shipping label. I do this because my business has an account with UPS and we get a pretty good discount. I also like to do it for tracking purposes (it is not uncommon to receive a error'd tracking number).
I would like to point out, every time I do it, I ship it to my Paypal confirmed address (which is my business), I tell the seller this, I provide the seller with my businesses toll free number, I provide the seller with my businesses website address (and inform them they can contact me via any number on the site or the e-mail links from the site). I always use the sellers name and address as the shipped from location (even if they are dropping it off at a UPS site).
But no, there is no guarantee that this results in a safer transaction. In fact, it could be less safe as with some shipments, only the shipper (or in this case, the account number holder) can re-direct a package.
My recommendation with any sizable transaction, get the buyers (or sellers) phone number and talk on the phone. You can get a good sense by doing this, including confirming the area code matches their location! FYI - my old trick used to be to ask people if I could pick up the item in person? If they said no, I became suspicious since a face to face transaction is usually the safest for both parties.
There was a time when I was picking up expensive speakers from a women in Ohio (she just went through a divorce), she was home alone when I got there. I called her from the driveway (how I found out she was home alone) and suggested she call a neighbor to come check me out. The neighbor (male) came out in 5 minutes. I suggested he take a picture of me with his phone, my car and my license plate (I was in the car when I said this). She watched this from her front door, I can tell you her demeanor changed dramatically. I ended up helping her sell her husbands entire sound system (he left her and moved back to Japan). She had no idea what it was worth. In the end, she got more than $20,000 from the sale of it. She sent half of the equipment home with me to sell for her (no, I didn't pay her for that stuff, just promised to give her all the proceeds, which I did).