At least there's no way to be sure of that. I may be wrong, but I've always envisaged the Basement as a sort of rumpus room where the guys got together to hang out. More than likely that big old reel to reel recorder was also used to play music, so when it came time to hit the record button it may well have been a case of rewinding the tape you'd been listening to, grabbing whatever blank tape was lying around and hitting the Fast Forward button until you reached a blank bit of tape.
There are reputedly, for instance, a number of previously uncirculated reels in Garth Hudson's personal archives.
What emerges from the sessions can be fairly easily sorted into a couple of categories, There's the stuff that turned up on the official Basement Tapes release and the Publishers' Demo previously referred to, the likes of I Shall Be Released, Quinn The Eskimo, Tears of Rage and Too Much of Nothing.
Then there are a variety of fairly well-known covers, including the Hank Snow/Elvis Presley A Fool Such As I, the Byrds-covered Pete Seeger Bells of Rhymney, Ian & Sylvia's Four Strong Winds (later covered by Neil Young), and Hank Williams' You Win Again. They're not straight readings of those numbers, more a case of familiarity with the tune and the words and a let's have a go at this mentality.
There's also a large quantity of less well-known material, largely from the folk tradition but drawn from other sources as well, and this is where things start to get interesting, and possibly a little off the rails. Brendan Behan's Banks of the Royal Canal, a sea shanty Bonnie Ship the Diamond, and assorted folk club standards along with relative obscurities that are starting to hearken back towards what Greil Marcus and various others tend to describe as the Old Weird America, material that was presumably brought to the table by Bower Bird Bob.
Finally there's a fair bit of what can only be described as goofing off. Variations on Bo Diddley, a bit of Flight of the Bumblebee, a delightful little oddity called I'm Your Teenage Prayer and See You Later Allen Ginsberg, all of which may well have come about as the result of significant herbal stimulation.