Fear of flying is more widespread than you might think and manifests itself in different ways. If someone just can't go on with the flight, then no crew member, including the Captain, has the right to imprison them on the aircraft. I suspect the disruption was minor compared to recent weather related disruptions. It is inconvenient to search and offload bags in these circumstances, but there is no alternative if a pax genuinely displays fear. Banning them will not help them overcome that fear! Have some understanding that not all your fellow pax are as comfortable with flying as you may be.
In the pre-911 days I found that taking a nervous pax to the flight deck and giving a brief explanation of our job, helped them relax - sadly OBL and his cronies put paid to that idea.
In these days of inflated hotel prices, a diversion of a full 747 or 380 will cost much more than £25k - it's the hidden costs of the aircraft and crews being out-of-position.