Its not the music stand per se, its the role it plays. An audience can tell whether the music stand (or whatever mechanism) is being used as an aide memoire in case a well-rehearsed piece needs prompting (perfectly acceptable) or whether, as seems increasingly the case, the artist(s) haven't bothered to try to learn their material and are relying on the dots, words, chords etc to get them through. This may sound contraversial but I'm afraid I feel insulted as a paying audience member if it is quite apparent that the paid (sometimes substantially) artist hasn't made any attempt to learn the material they are presenting.

In an environment specifically created to provide a "safe" learning space and encourage people to try out new pieces or pluck up the courage to have a go, music stands and the stuff that goes on them are perfectly acceptable - its part of the safe environment.
Chips