[to1y]

it's considered very bad form, especially in orchestra's , _especially_ by the conductor because it means 1. you're not following them 2. it's very distracting for the audience/other members of the band 3. it's a 'beginner' tendency, shows lack of self-control.

[dwringer]

I've played in a few orchestras in my life and never heard that opinion (other than the part I previously mentioned, when it becomes a distraction to the audience), but I suppose some conductors may feel differently.

[to1y]

My experience is it was relentlessly drilled in all early students