Gigging is great fun and should be treated as such but yeah u still gotta hit the right notes.
If u dont depending on what piece your playin u can normally blag it.
I usually concetrate on the numbers where the bass is more prominent and then have fun with the numbers I dont have to worry about too much.
As for people in the audience knowing when you have made a mistake, no one seems to notice and even your band mates might not notice.
I played one gig where I was reasonable and then descended into poor, my bandmates said " U were really good tonight" I must have blagged better than I thought, I couldnt help but smile.
U are always learning, there is some bass lines I wouldnt have dreamt of attempting a year ago but with a bit of effort and persevearance u do get there in the end.
Above all else I agree with everything that has been said especially staring at one woman, the only way to get away with it is where shades.....