A lot of misunderstanding of the point of the ban going on in this series of posts. Yes, he might well get in, but the risks are very high. The point of the ban is that there person has been warned that any appearance on the owners property is not authorized and will be considered criminal trespass. So, since you know you aren't supposed to be there simply being there IS the crime and no further proof is needed. Criminal trespass and criminal record.
So, sure he might well get on grounds but the method is a moot point. Get caught he'll pay big time. And that's the real point of the ban. Make the consequences so high that the risk of running around backstage isn't worth it. It's now no longer a fun adventure, it's no a crime with serious consequences.