The absence of border control at internal borders shall not affect:

1. (a)

   the exercise of police powers by the competent authorities of the Member States under national law, insofar as the exercise of those powers does not have an effect equivalent to border checks; that shall also apply in border areas. Within the meaning of the first sentence, the exercise of police powers may not, in particular, be considered equivalent to the exercise of border checks when the police measures:

   1. (i)

      do not have border control as an objective;

   2. (ii)

      are based on general police information and experience regarding possible threats to public security and aim, in particular, to combat cross-border crime;

   3. (iii)

      are devised and executed in a manner clearly distinct from systematic checks on persons at the external borders;

   4. (iv)

      are carried out on the basis of spot-checks;

2. (b)

   security checks on persons carried out at ports and airports by the competent authorities under the law of each Member State, by port or airport officials or carriers, provided that such checks are also carried out on persons travelling within a Member State;

3. (c)

   the possibility for a Member State to provide by law for an obligation to hold or carry papers and documents;

4. (d)

   the possibility for a Member State to provide by law for an obligation on third-country nationals to report their presence on its territory pursuant to the provisions of Article 22 of the Convention implementing the Schengen Agreement of 14 June 1985 between the Governments of the States of the Benelux Economic Union, the Federal Republic of Germany and the French Republic on the gradual abolition of checks at their common borders (‘the Schengen Convention’).