I think we are all critics by nature, even if not adjudicators. When we are listening to a performance we tend to judge it in our own minds, and those of us who play are probably watching out for the technical skills or otherwise of the performers.
I would say, however, that most of us would be more tolerant of the occasional slip than an adjudicator would be. I, for one, am more interested in a good overall musical performance rather than waiting to see if the soloists hit their top "z".
The other thing that troubles me somewhat is that, with the abundance of first-rate recordings available, audiences can be over-critical of mistakes made in live performances of all kinds of music. We are so used to the standards produced in a studio, with retakes and editing, and also to simply sitting back and listening instead of contributing to the success of a concert as members of the audience. Building a rapport between performer and listener is a two-way thing, and too often audiences seem content to let the performers on stage do all the work.