Otherwise, dogs can frequently be seen in restaurants and cafes, though they are usually tied up to wait for their owners outside of grocery stores. To travel on trams, buses, or the metro, pets must either be held in an enclosed space such as a bag or cage, or, in the case of dogs, kept on leashes and wearing muzzles. Bus or tram drivers have the option of refusing to allow a dog on board (if there isn´t enough space, etc.), but this occurrence is rare. If they are not being carried in a container, dogs require a 20 CZK, single-use ticket for all forms of public transport.