It isn't so much that people shouldn't go there, but perhaps that the people who are going there shouldn't. A BBC crew isn't a tour group. They are reporters with an agenda. That agenda may only be to tell the truth, but truth telling in NK is a big deal. And every time I hear about a westerner being detained, I feel obligated to dig into things to see whether they were in fact a religious zealot actually seeking to do exactly that with which they are accused. Admittedly that isn't the BBC, but westerners working for "charities" in places like Afghanistan or NK often turn out to be secretive missionaries trying to proselytize their faith.