What was the point of that? He could've just operated as a business man, or just someone with an interest in the blockade of Naboo. It couldn't have been to let the Jedi find out for themselves, because he had Maul to do that. Perhaps he used it to terrify them into doing his bidding, but wasn't that taking a great risk? He didn't let them know that he was Senator Palpatine, but one of the Neimoidians did turn his head as he passed Palpatine towards the end of the film, as if he identified him. Throughout the film, the Neimoidians remained very nervous about the alliance - they knew if the Republic or Jedi found out, they'd be in big trouble. They went with the alliance out of greed - but to their downfall. I don't see why he had to let them know who he was at all?