Travellers from or to some countries experience considerable difficulty and delay in obtaining travel authorization (usually visas). Some countries charge exit visa that hinders the travelling of e.g. students. Clearance through customs can be a major ordeal with lines causing an hour or more of travel delay. Delay may also be experienced at the frontier when further questions may be raised which have to be answered, in many cases in detail on special forms. These difficulties may be considerably increased in the case of travellers from countries which do not have diplomatic relations with the country visited. In the extreme case, travellers from such countries may be obliged to initiate requests for visas many months in advance, ensuring that the visa for the last country visited prior to the return is obtained before that for the previous country, and so on for each country back to that first visited after departure from the traveller's home country. While these problems may be, in the main, of an a administrative nature, there may be political discrimination against citizens of various countries, involving a number of further additions to the formalities.
Visa and frontier formalities frequently give rise to occasions for bribery. Visa possession and ability to cross a frontier has been a matter of life or death in numerous countries for those seeking refuge from injustice. The advent of computer-controlled crossing points may impose additional problems including the threat to freedom of movement.
Frontier controls are essential to curb drug traffic, terrorists, illegal immigration and other serious crime which often come from outside the country. In many cases, the management of these problems requires controls, restrictions and special police powers.