Our contracts used to have the phrase, "upon presentation" for offer expiration. I used to get tons of flax for doing this but would retort the Seller probably KNEW what they would take for their home and could make a decision that night. I never got the other two offers presented as they accepted his reasonable and fair offer. Lowballers pulling this would probably be told to present the other two!! Nowadays most offers are increasingly being 'faxed" on over. So a cover letter works. You won't pull this with a REO.
However, presenting offers without disclosing could be considered "negotiating in bad faith". This seems to be very common with the "short-sales" out there. Present offers, let them sit around for a few months and walk when you find a more cooperative Seller. Just be careful about contract obligations if someone accepts!! You just can't "change your mind" to get out of a contract!
The situation with that buyer was that the offers he was making were extreme "low-ball" offers, so it would have been surprising if any of the sellers had accepted. My seller was extremely offended, not only by the low-ball offer but by the buyer's multiple offer scenario.
The thing you want to guard against is being committed to buying two homes if both offers are accepted.