Awe are a little drifting from core UNIX but FWIW: With the noise made about the ACM DL is more freely available and the 'advertisement' they sent saying the earliest UNIX paper was now there for anyone to examine (from the 1973 SOSP), I just tried to download both without signing in and with -- I got the same result. You get the abstract - not the paper which was a tad disappointing. FWIW: from the SOSP was Jerry Popek's famous paper on requirements for VM -- same result.
I understand the problem, (USENIX also has the same one) but it seems like if they are going to scan things, scan all of it, not just the abstract.