You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Dog

Context:
In Islam, dogs are viewed as unclean because they are viewed as scavengers. In 2015 city councillor Hasan Küçük of The Hague called for dog ownership to be made illegal in that city. Islamic activists in Lérida, Spain, lobbied for dogs to be kept out of Muslim neighborhoods, saying their presence violated Muslims' religious freedom. In Britain, police sniffer dogs are carefully used, and are not permitted to contact passengers, only their luggage. They are required to wear leather dog booties when searching mosques or Muslim homes.

Question:
What are sniffer dogs used by British police allowed to touch instead of a passenger?

their luggage