Nice to see someone has invoked the shade of Chris Boyce. His ET Presence, the sequel to “ET Encounter” which he started on-line in the late 90s, has this intriguing perspective on the presence of von Neumann probes or machines in our system:
As things stand we have no evidence of contact between humanity and vN. Logic does dictate that if ET societies exist vN are virtually certain to be in the Solar System, perhaps with a presence here on Earth or close by. In this event they are leaving it up to us to find them and make up our own minds as to whether or not we wish to knock on their door.
Over the next few centuries we may seek them out, perhaps find them and try to communicate. Or we may simply go our own way and choose to ignore their presence.
But whether we do or not – they are real and they are here.
Thus all our discussions about their existence and contacting them are irrelevant to the reality of the vN presence, who will go on ignoring us – except they’re likely to be monitoring all our discussions. It’s not the first time someone has raised that possibility, but no ETIs have made themselves known so far. If they’re nearby then we may need to knock. Carefully.