they don't know if the buyer is 'blowing smoke', but it's none of their business.  They accept the offer or they don't.  There is no regulation that they have access to other offers.  That is also none of their business.
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If they make an offer that puts them in a negative position, that's their own fault (and their agent).   The seller is not responsible for what they buyer puts in their offer and does not have a duty to disclose extra information to them