Out of curiosity, is it considered rude to offer a seller more than BIN the seller set, in order to receive the product over the person who offered the BIN?
I'd consider this competitive and rude. The BIN was already set and if the BIN bidder pays, they should receive.
yes, technically it is not nice. Some auctions in forums state "Highest bid above BIN wins" but in that case, the BIN stated is not the BIN then but the "Reserve Price". The BIN is a first come first serve rule- whoever is first to pay the BIN wins the auction and the auction is closed at that point and all future higher bids than that are NULL. The Auction rules in forums can be subjective and not so professionally done unlike automated auction marketplaces like ebay