I've seen a lot of traditional bands on stage in the last 20 years. Here are a few things I've seen that denote real lack of showmanship.

1. When a number is done, the audience applauds enthusiastically, but the musicians hang their heads as if ashamed. They don't smile, say thank you or even look at the audience.   

2. One band member does all the talking. Are the others deaf and dumb?

3. In the words of a friend of mine, a band member plays like a demon, then sinks into a trance. Has he any interest in us?

4. The audience members are nicely dressed because this is a special occasion to them, but the musicians look like they live under a bridge.