Television stand-up comedians such as Arthur Smith sat around with the usual comedians' off-stage demeanour of unalloyed gloom. Audience members coming out of the Hull Truck Company's latest play had the special Edinburgh experience of chatting to playwright and cast at the bar.
Then something unusual happened. A young woman from a production elsewhere in the city handed out leaflets for her show, as happens a hundred times a day. A posse of uniformed staff pounced and took the leaflets out of people's hands: the show was at another venue and could not be advertised there.
The Edinburgh Fringe, known for decades as the largest, most anarchic and most comradely festival in the world, has this year become coolly professional. It may never be quite the same again.
By Thursday afternoon, Addison Creswell, manager of comedians such as Jo Brand and Jack Dee and a festival regular for the past 12 years, had decided to go home. 'I hadn't been back to London during a festival before,' he said. 'But you can get really burnt up here now. The venue rents are so high you have to sell out every night to make money. And it's pounds 350 a week for a city-centre flat. The whole thing has become money-orientated. I have to come here as it's the only place I can talk to TV people, but the place has lost its buzz.'
Similar accusations were levelled by Donald Gorrie, an Edinburgh district councillor who sparked a public debate with a furious letter to the Scotsman pointing the finger at a new super-Fringe - the coming together of the three top venues, the Assembly Rooms, Pleasance and Gilded Balloon, for programming and marketing purposes under the canny management of the urbane William Burdett-Coutts, 38, director of the Assembly Rooms, head of arts at Granada TV and a member of the Coutts banking family.
Mr Gorrie says: 'They have a separate brochure, larger and glossier than the Fringe programme, and a near-monopoly on media coverage. There seems to be the intention and certainly the risk that a two-tier Fringe will be created. Once they have a monopoly of the hyped-up prestige venues, the promoters can hold performers and audiences to ransom. The diversity of the Fringe will be destroyed.'
Mr Burdett-Coutts retorts that it is only by coming together that the top venues can survive. His own is threatened with a doubling of rent for the festival to pounds 65,000 by Edinburgh council. But he admits that the typical company appearing on the Fringe will be lucky to break even. Community centres on the edge of the city can still be hired for pounds 50 a week, but a hall in the Assembly Rooms is likely to be nearer pounds 4,000.
For Mr Burdett-Coutts, the entire way the festivals, official and Fringe, are sold needs revamping. The official festival, he says, needs a mega-event, a Pavarotti in the Park, that is talked about for months. A four-hour Julius Caesar in German, which has not sold out despite being directed by the celebrated Peter Stein, is not the same thing, he says.
He adds that visitors should be able to buy tickets for all the festivals - official, Fringe, jazz, book and film - from one building rather than have to walk all over town, and there should be ticket-and-travel packages. Both the festival and Fringe offices agree privately that this must be sorted out by next year, though they point out that ticket sales are well up and the public is revelling in the festival in a week of unusually good weather.
There have, though, been notable failures. As Paul Blackman, head of the BAC theatre and comedy venue in London, observed: 'There is definitely a two-tier Fringe now, but the capacity to fail or succeed still exists right across the spectrum. Margi Clarke's (star of the film Letter to Brezhnev) one-woman show is one of the worst things in town.'
Other famous names to have come unstuck include Peter Sellars, wunderkind American avant-garde director whose much-vaunted official festival version of Aeschylus, The Persians - complete with Saddam Hussein and Stealth bomb references - received some of the rottenest reviews seen for years; and, on the Fringe, Arthur Smith's latest play, Sod, was getting a cool reception.
Few critics, however, could match the faint praise given by veteran Scottish comedian Jimmy Logan, who is mounting a variety revival of the official festival. He congratulated the young alternative comedians on the Fringe for being challenging and refreshing, but added: 'They don't quite know how to walk on a stage, or how to walk off a stage, or how to hold a microphone, and the way they dress they will never play the big theatres.'
It must have made them feel almost anarchic again.