You make a good point, banning him because he might cause civil unrest makes a very good case that Wilders is correct about radical Islam being violent. The trouble with your interpretation is that in terms of cageyness has somewhat dissipated in light of their subsidies of and acquiescence to radical Islam in their culture. So, I really think they’re just being pigheaded about arresting him.
Quite likely ... Gordon Brown is utterly out of his depth, and this is in line with his past behavior.
Nevertheless, even if they didn't mean to do it, this little charade has made the point far better than letting Wilders in could ever have done.