The prosecutor would have the burden of proof to prove guilty beyond a reasonable doubt.
Of course -- successful prosecution would be all-but-impossible if a requisite element of the crime could not be proved. However, the issue I'm raising isn't a conviction under the statutes/ordinances/regulations, but rather the hassle and expense that would be involved with "beating" such a conviction.
one thing to keep in mind...
copyright is a civil case, not a criminal prosecution.
Civil cases do not require "guilt beyond reasonable doubt". They are a lot easier to win a case/lawsuit. But, that said, I've been in the business of talking copyright law, being a musician & photographer. Copyright claims are not cut & dry.
In photography, the photographer is the copyright holder, the moment he presses the button to release the shutter & captures the image. The only exceptions are, if the photographer was on paid assignment as an employee of a company, taking photos for them. Then, they belong to the employer.
Photographers can also get into trouble (copyright conflict) if they take an image of someone else's copyright work. A few years back, the issue of tattoos on models, where the tattoo is someone else's copyrighted work. IIRC, a famous case was Mike Tyson's facial tattoos, where they were unique & the artist was well known.
So, that begs one to ask, is the recorder/taper the copyright holder, as is the photographer? But, is he then capturing a copyrighted work?
Yes, similarly, it works the same.
Now, to the brass tacks.
To claim a copyright. or trademark infringement, you have to have "damages". You are suing for said damages & what you consider fair compensation, based on either/or, monetary loss to you, or monetary gain by the infringer.
How much money does (in this case) the band lose, by simply you recording them? How much money did you gain? Chances are, most here are not recording to sell, but, let's say that they thought some money was being made by you, or from you.
I knew a guy, who took a picture. It was a portrait. Funny enough, he was watching a blockbuster movie, & saw his portrait in the movie. He showed a few people & people encouraged him, that, he was the copyright holder, & the movie used the image w/o his permission & that the movie obviously made millions of dollars.
Sounds like he has a case & a good one. Likely a big payoff... until, all the explorations of copyright law & damages came into play. He had to prove damages. It didn't hurt his finances, nor his reputation, but, there was the idea of being used in a production for profit medium.
Then, the questions came up, how integral to the movies success was his particular image? What percentage of the movie did the image occupy? How much money was the particular image responsible for contributing to the profits?
Or was in inconsequential?
Ended up, after the lawyer explained all that to him, he realized that he really didn't have much of a case. He could have went to court to sue the studio, but it would have cost him thousands of dollars & probably, the outcome would have been that either he lost, or, the studio would have to go back & remove the frames that included his image.
The image was displayed for about 3-5 seconds & was among a table & wall of about 25 other pictures. It was never shown close-up, nor displayed as of any importance.
So, being a musician, having someone record one of your shows, & maybe trading it to friends, or keeping it to him/herself, there's going to be all that damages thing to prove. They might shell out thousands of dollars & the best they might get, is a copy of the recording from you... which, you'd probably give them if they wanted it anyway.
Now, think of the thousands of people recording your shows...