【明報專訊】THE SAR GOVERNMENT and mainland public security authorities have signed new arrangements on the reciprocal notification mechanism. Time limits have been set for the notifications of various kinds of cases and the scope of cases to be covered has also been widened. In the Causeway Bay Books saga last year, bookstore owner Lee Bo went missing for many months after he had "returned to the mainland using [his] own methods". The government had tried many times to contact the mainland authorities by means of the notification and collaboration mechanism but after a long time it still got no detailed replies. Technically speaking, implementing a new notification mechanism will, to a certain degree, help avoid a communication gap between law enforcement departments of the two sides. But still it may not be enough to dispel Hong Kong people's political doubts. If mainland officers cross the border to enforce laws, even a new mechanism in place would only be futile.