A question came in regarding a specific work that had sections marked muted but there was no time allowed to put in or take out a mute, even hanging it on a string. It was a specific work but the answer relates to lots of works where this same thing occurs.
- Don’t ask the conductor! They have no idea what to tell you and
- If there is no time to make the mute change then play it stopped (with the hand).
Most likely that is what the composer actually had in mind. Words get thrown around pretty loosely at times. My general working theory is that the composer was thinking the hand to be a type of “damper” that modifies to the sound. So yes, it may be marked “mit dampfer” for example, but just play it stopped, it gets at the effect.
And don’t ask the conductor! There is a pretty good chance that they won’t give you the answer you are looking for, and also most likely they won’t even notice you are playing stopped rather than muted.
Ideally you should agree as a section on how to approach the problematic passage, and it is worth noting as a final point that you should always individually feel free to use a stop mute instead of hand stopping if time allows or if the most important notes really require it for intonation or to be heard at all. My introduction to hand stopping is here.