Organising a Conference
"Please send us your frozen peas."
"I will bring fresh peas on the day."
"How many peas? What kind of peas? Freeze them now and send them."
"They're not ready yet."
"We need to know what they taste like."
"They're peas. I grow them. I am growing them for you. For free."
"You have to serve them on our plates. We have a waiter. He's trained on plates, but needs your peas now to see if they will work."
"I'm a pea expert. That's why you invited me."
"We are preparing a report on our pea tasting before it happens so we need your peas now to have it ready beforehand."
"Oops. Just checked. They're actually beans."
In both cases, the [slightly passive aggressive] approach that I'd recommend is to supply a pdf (or ppt) with just 2 slides in it: - A cover slide, with the work placeholder visible but not unduly prominent. - A slide containing words like "This in-advance deck is simply a placeholder, the full slides will used during the presentation."
This allows the mindless wheel squeaking to stop ("I've already sent it to you, it is not necessary to ask again."), and if someone really is preparing a premature publication will at least mean that your missing slides don't look too odd.