I think it's probably bull. I searched here, where the setlists are fairly comprehensive and it doesn't appear.

On Google Books, Turn Out the Lights: Chronicles of Texas During the 80s and 90s (improbably) writes,

"The night after she died, most of Joplin's friends gathered at the Landmark Hotel in Hollywood. On that occasion, Kris heard for the first time Joplin's version of 'Bobby McGee'. Twenty-six years later, he saw a tape of her singing it at Threadgill's in Austin."

So I would have to say it's possible. But it's also possible that she's just tweaking her memory. I recently read (was this on mefi?) that people keep coming up to the Big Brother guys and saying how great they were at the 1967 Human Be-In, but they didn't even play ....

I knew I could rely on you guys! dhartung's comment led me to investigate Threadgills in Austin, and I came up with this link.

Excerpts: "In July [1970], Janis literally returned to her musical roots when she traveled to Austin to help friends celebrate Kenneth Threadgill's birthday ... Once in Austin, Janis assumed a low profile, although she did sing a couple of songs for the crowd of eight thousand that turned out to honor Threadgill. After announcing she couldn't sing rock 'n' roll without her band, she asked for her "gitar." "Will someone tune this thing?" she said, adding she couldn't tune "worth shit." She then launched into two Kristofferson tunes, "Sunday Morning Coming Down" ("Almost as bad as Tuesday morning coming down--or Thursday morning coming down," she joked) and "Me and Bobby McGee."

I suppose it's possible that my acquaintance had the singular good fortune to be one of the crowd of 8,000 at Threadgill's birthday party. Serendipity, by definition, is a weird thing. When I see her next, I'll make sure to ask her where she caught this live performance.

Thanks, Essexjan and dhartung!

I read somewhere (Phil Lesh's memoir?) that Janice and Bob Weir taught each other that song while on the Festival Express train trip across Canada in 1970. I guess it is possible that she performed it at one of those concerts.

The interesting musical note to the story was that they had the words and the chord structure, but not a recording by Kristofferson doing the song. That, apparently led to both of their versions being fairly different from his.

I was about to say the same thing as mmahaffie. I checked Deadbase, but it wouldn't show up there unless Janis performed it with the Grateful Dead.

That looks like an awesome documentary, mmahaffie. I'm going to keep an eye out for it. Thanks.

Speaking of musicians from the Sixties, it looks like Dennis Doherty died today.

That, of course, should be Denny Doherty, not Dennis Doherty. Preview's for the boids, apparently.

For what it's worth, yesterday would have been Janis's 64th birthday.

I would be skeptical of it also. No way she ever played it with Big Brother. They were one of the few acts that I DIDN'T see back then, though.

That looks like an awesome documentary, mmahaffie.

It is and it isn't. Half of the movie is the musicians jamming on the train, which is interesting. The other half are onstage musical performances from the various locations where they played. About half of those seem to be the last or next to last songs from the given act's encore. This makes for some pretty bipolar segues.

My gripe with the plethora of encore peformances is a suspicion that they were not the best musical choices. I would rather have seen Buddy Guy actually playing guitar rather than making with the crowd pleasing showman acrobatics, even if he was really revved up.

And I could have done without all the talking head shots of the artists still alive today. It's like they were trying to pad out the movie with filler. It makes me wonder just how much footage they had in that vault.