Customs can check your hand and hold baggage. Customs also has the right to perform body searches. Customs may use various aids in the performance of their checks, such as sniffer dogs or a scanner.
Part of each customs check involves the Customs asking questions, such as 'What is the purpose of your trip?' or 'How did you pay for your flight ticket?'.
You must fully cooperate with the customs officers and answer all their questions truthfully and completely. Failure to cooperate fully is a punishable offence.
There is a possibility that Customs will check your goods when you are not present. By using a TSA lock you reduce the chance of damage to the lock of your suitcase during an inspection. In case Customs opens your luggage when you are not present, you will be informed about this. For example, through a form in your luggage.