While I think its a great scene and Michael looks really suprised when Vito tells him "and you'll be assassinated"

Couldnt Michael or Tom or Neri eventually figure this out in time to not have the meeting or something else?

The scene is what it is. The answer to my question BUT could it have been possible that Neri says "smells like a trap" or "why is Tessio setting up meeting" etc etc...