Hi! As a seller on Ebay and owner of an Ebay store, I know that I tend to be generous with the tape. And, believe me, my handling charge doesn't even cover the cost for the mailer, let alone tape and bubble wrap. Sellers are truly caught in a no-win situation.... too little tape and the package can open. Or, if any spaces are left, moisture can get into the package. Despite my best efforts, I just had a buyer email me that her priority mail box arrived with gouges and her papers were all dented. She was frustrated and I am taking a loss as I am replacing the entire contents and re-shipping at my expense -- for something totally out of my control.
If you want to make sure that your seller doesn't over-tape packages, send a little note and ask them not to mummify the package in tape and mention why. I am sure they would be more than willing to be accommodating.
Over the last few months, Ebay has instituted a new methodology for determining seller final value fees and results in searches. Ebay has some sort of secret formula using the seller's feedback scores and DSR ratings (those little yellow stars) to determine where a seller's product shows up (if at all) in buyers' searches. If a seller has a DSR rating under 4.3, their account is actually suspended. So, please, be gentle when leaving feedback. Too much tape does not mean a bad seller, just a little over zealous.