Nothing Will actually happen. The buyer/seller may become annoyed but you can not be penalized or warned for not leaving feedback.
Feedback is made for the satisfactory of saying 'Thankyou' for purchasing/selling a specific item.
If you have been reported more than once, your account can be suspended or closed down
You can't. The feedback left / received is permanent.
You can't. The feedback left/received is permanent.
new accounts
first leave negative feedback then report them to eBay
not if you check feedback
No most of them are not. They can make big profits on ebay.
76,000
Check the seller's feedback.
first leave negative feedback then report them to eBay
To leave feedback, you need to be in a transaction with another eBay member (that is, you need to be either the winning buyer or the seller of an item). You can only leave feedback once for each transaction, although you can also leave a follow-up or reply by going to the Feedback Forum (which you can find by using the link at the bottom of any eBay page). If you are eligible to leave feedback (as above) but are unable to, try again another time.
You can't do anything unless they actually bid on your auction. Even then there is no legal repercussions. Leaving them negative feedback is all you can do.