increpatio, I did in fact once turn up at a concert by one of our Members expecting to be in the audience and found myself sitting on stage with among other things an aleatoric score in front of me. The Member in question had planned a path through the score which involved for example removing a page and then putting it back again after the next page had been played while removing a page from behind it. All this without being dressed for the gig. And then there came a piece where the composer had choreographed the fingerings so carefully that the pianist's elbows would fly up without warning as for example the left little finger played notes higher than the left thumb. I don't know if said composer had incorporated as a parameter the likelihood of the pianist's elbow striking the page-turner in the groin on its flight but I wouldn't put it past him.

If this is indeed the piece I think you are talk about, I have actually witnessed a groin-striking (albeit in reherasal, not performance) during this piece. 

It is time to own up to being the Member in question who rendered on this occasion (and others) a certain piece by one Member quartertone that could be interpreted as entering into a somewhat problematic, antagonistic and physically defamiliarising relationship with its page turner's pride and joy. I do not believe this is an intentional component of the piece, though (if it were a piece by Hespos I might think differently on that subject).  Also, the aleatoric score in question is Gilbert Amy's fantastic Piano Sonata, a very little known work, clearly influenced by the Boulez 3rd, but on a much more complex level (in the most banal sense, it uses five colours where Boulez uses two). The open form procedures are themselves quite complex, and only a turner such as Member Sudden would be able to navigate the various backs and forths involved (Thanks!).

Now, 'sambeckett', are you who I think you are? Did you witness the incident in question this very year?

By the way, I did once suggest to Dieter Schnebel the idea of a piece for solo page-turner (bearing in mind his work Nostalgie for solo conductor, and the piece from the Visible Music series for solo instrumentalist and conductor). Nothing has come of that suggestion to date, to the best of my knowledge, though.

A certain Member Lenz here has an instruction saying 'Page turner turns page as if in slow motion', which could be seen as a step in this direction.

"As if" in slow motion but not actually in slow motion . Ms Lenz's requests can be very specialised. "Quasi-deliquescent ma non troppo" IIRC?

Harawi is another potentially risky one for the page-turner's future reproductive capacities. Especially the movement which has all those horn fanfares in the middle register punctuated by sudden (no not Sudden) plunges to Messiaen's favourite lowest A-Bb-B mini-cluster. Have to watch for those.

piapiapiapiapiapiapiapiapiapiapiapiapiapiapiapiadoundoutchiltchiltchil...

brrr.... it's a horrible thing to turn pages for pianists. Fortunately I haven't had to do it in concerts, but recordings are even more pressured. I always bugler it up....

Back in 2005 I turned for Hamelin recording Abel Decaux for Hyperion. Terribly complicated stuff for all concerned. Worst of all, when he finished the complete take of the last movement, which ended with a long sustained chord gradually fading into the æther, my tummy decided to have a good gurgle (luckily during the silence). The mic's picked it up.  Of course they removed it, but all the same... not to be repeated...

I'm pretty positive it was Fox's More Light (beautiful piece, for those who don't know it), not lliK.relliK? I do remember the concert well, and don't remember a problem in that piece (but this is eight years ago). Poor Fred had to negotiate not just that, but also Barrett Tract, Dench Topologies and Finnissy English Country-Tunes all in the one programme. He did a sterling job!

Oh dear, I worry I might be know as a page-turner's nightmare. Can I plead that it's the composer's fault, not mine (I do play most of the notes on the page, I think)?  There was one time I sent a page-turner away, when they couldn't even follow the Webern Variations in rehearsal, which suggested that Stockhausen Klavierstück X might be a bit of an ordeal.

One story I may not have related here before, involving other extra characters on stage, was when I did Patrícia Sucena Almeida's piece fatus hominis in Oslo. This piece requires the pianist to be on stage in complete darkness except for a light on the music stand. When they walk on stage there is a candle which they light before playing. Standing at the back of the stage are two mysterious figures wearing gowns with hoods - at the end of the piece these two individuals come up to the pianist and one covers him/her with their hood, whilst the other blows the candle out. Heavy goth-style imagery (that's very much her thing); problem was that the two figures in question, who on this occasion were played by Messrs Barrett and Foerisdal (Norwegian guitarist) both looked exactly like the Grim Reaper figure from Monty Python's The Meaning of Life. This theatre piece is supposed to be very atmospheric, bleak, somewhat disturbing, but when confronted by these two individuals just before walking on, it was very hard for all three to avoid rolling all around the floor in mad laughter, a repeat of a situation in the rehearsal which had somewhat perturbed the composer! Straight faces were maintained in the performance, but not without considerable effort..... 

George Brecht's 2nd symphony fits the bill . . .