Rosenkavalier conundrum

Now Hugo von Hoffmanstahl's libretto for Der Rosenkavalier is one of the great libretti in operatic history and virtually a work of literature in its own right. It was carefully constructed by Hoffmanstahl and Strauss so must be exactly what was meant. Which leads me to the oddity of the opening of the 3rd Act. What is going on?

Now, we know that Octavian and the Italian intriguers are planning a trap for Ochs, the intention being to get Ochs to try and seduce Mariandel (Octavian in disguise), with a false message to Faninal ensuring that Ochs prospective father-in-law sees what a rogue his son-in-law really is. Annina (the female Italian intriguer) is pretending to be Ochs's wife and children have been hired (in many productions these are the 3 noble orphans from Act 1).

That it all goes horribly wrong because of the presence of the Watch, Sophie Faninal and the Marschallin is quite clear.

But why on earth are there a bunch of blokes who are hidden in trapdoors and other places around the room. What have they to do with Octavian's plot? Is his intention to scare Ochs so that he behaves irrationally? When I first read the libretto I had assumed that they were being hidden so they could spy on Ochs and Mariandel, but a careful reading of the text makes it clear that they are there to jump out on signal, something which is included in Strauss's orchestration. They feel redundant and seem to be present simply to add a bit of fun, so that the open of Act 3 can have the requisite busy-ness. I have often wondered what a cut Act 3, shorn of this business would be like. The opening section would be far shorter, just an orchestral prelude perhaps with a short scene between Octavian and the intriguers before Ochs comes in. Then the incursions of the hidden men later on would be removed. What would the effect be, better or worse?