You will not hear from the organizers unless they decide to use your paper.It started with one leading group's calls, which go so even farther:
You will not hear from the organizers unless they decide to use your paper. They are not journal editors or program committee chairmen for a society.Now it's spreading.
Bad form, folks.
(1) It's rude. Submissions are not spam to be acted upon by the organizers if interesting, and deleted otherwise. On the contrary, they're solicited, so the least the organizer can do is acknowledge receipt and outcome with costless "thanks for your submission" and "sorry but we couldn't use your paper" emails (which, by the way, are automatically sent in leading software like Conference Maker). As for gratuitous additions like "They are not journal editors or program committee chairmen...," well, I'll hold my tongue.
(2) It's risky. Consider an author whose fine submission somehow fails to reach the organizer, which happens surprisingly often. The lost opportunity hurts everyone -- the author whose career would have been enhanced, the organizer whose reputation would have been enhanced, and the conference participants whose knowledge would have been enhanced, not to mention the general advancement of science -- and no one is the wiser. That doesn't happen when the announced procedure includes acknowledgement of submissions, in which case the above author would simply email the organizer saying, "Hey, where's my acknowledgement? Didn't you receive my submission?"
(Note the interplay between (1) and (2). Social norms like "courtesy" arise in part to promote efficiency.)