In all cases, the listing agent (assuming there is one) should confirm receipt of the offer.
The Listing Agent is working for the Seller.
The decisions are the Sellers.
That said; you must realize that etiquite and courtesy are not something that was handed down to this new generation; probably not the last one either!
Particularly in Multiple Offer situations, I am not seeing the slightest courtesy to the "other" bidders on a house. I wouldn't hold my breath. Just move on, and don't let it get to you.