All they had to do would be to simply tap into the systems and listen.

Global communication was already there, just as computer networks used by banks, universities and army. After all, Unix was kickstarted in 1971 because it was needed, not because it was an experiment.

I pity the handful engreyneers left behind to keep their listening equipment adapted to our wildly fluctuating network protocols.

(TCP/IP hails from 1974 and when I became a sysadmin at my U in the late 80s, DFN grants still came with a Thy Computer Shalt Use X.25 To Network requirement.)

"RFC 1356 shall NOT PASS!!"

[shrug] May have been (secretly?) in effect on the USENET server back then, I wouldn't know. My e-mail address at the time was not RFC821 but X.400, though. (And hosted outside my purview as well.) First grant actually paid out to us resulted in a bunch of SUNs, and thus TCP/IP (on Thinwire), which had gotten blessed by DFN in the meantime.

Pre-internet, going back to at least the mid to late 1960s you had regional and some global vendor-specific networks (IBM SNA, Digital Equipment DECNet, CDC Cybernet, and probably many others), and the X.25 standard, and TCP/IP, but none was close to being dominant or ubiquitous by any means. Late 1980s, you had a downright standards war between some favoring moving to X.25; TCP/IP; and ISO OSI standard. We were VERY close to running OSI today, but the vendors in the late 1980s adding both IP and OSI to their OSes, OSI was a bit over-engineered so they'd get TCP/IP available sometimes in a matter of months, with full OSI support planned for several years down the road. ARPA of course favored TCP/IP, and NSF (National Science Foundation) did as well; but quite a few European networks were firing up with OSI, and basically only switched to TCP/IP due to so many systems already having IP stacks ready while their OSI stacks were still under development; given their goal was to get these educational and research networks that, you know, they could hook their stuff into, they didn't want to wait 2 or 3 years for them to get their OSI stacks in shape. I was in like grade school at that point but it's amazing to read about in the online historical documents.

While the beginnings of what would become operating systems and the modern day internet may have begun in the 70's I still find it hard to belive that anything they did that far back would somehow still have traces in today's computer systems and networks. The way IT updates in modern times, it would be hard to imagine traces remaining from even 10 years ago.

More likely they have continued to hack and cover their tracks, much like the Raharr's recent hacking actions. This would either suggest they retain a presence on Earth or they have some technology on Earth which continues to function and hack systems, much like the Raharr satellite.

...Alternatively, there is a third alien species/group which found Earth more recently and conducted network hacks, covering their tracks afterwards.

Surprisingly, there's Usenet archives (a global distributed bulletin board system) going back to the 1970s (people found tape archives of these and they are now avialble online). The amount of total traffic was low, like 200MB a year or so back then. And actually a surprisingly large amount of information going back to the early 1990s. Like a lot, both internet stuff and from pre-internet "connected dialup bulletin board" systems like Fidonet, and some from the systems like DECNet, SNA, etc., that had E-Mail and bulletin board systems (also file archives, Fidonet, etc. did support requesting a file and having it show up eventually on your local system. Some of these were 'store and forward' so a file would show up on your system days later, but it'd get there eventually.)

That said, I did have the same conclusion you did, I took it to mean they have detected signs of recent and ongoing tampering.

Seen from their point of view , they would not fulfill their commitment to their

nations / all of us. if that exact thought had not crossed their minds.

We as readers from the sidelines have formed a different opinion but most people outside the 3 Stooges in this world-setting, would be concerned about a

"shadow invasion" going on, one slice of Salami after another and then....

BAM! : "All your bases are, belongs to us"

TBH aliens already did "admiral Perry" thing to Earth, so they have no reason to sugarcoat their demands.

We can consider ourselves a polar bear, securely fitted with a radio-transmitter by some biologist.

They don't need to interfere with us, since there's no way we're getting out of their reach.