I watch that show as well. But I don't remember if they simply asked the person if they could search or demanded that they be able to search. Anyone who watches reality tv (for example 'Live PD') knows there are many cases where the police officer simply gains consent from the suspect for a search without any particular legal reason or right to do so. Now if they suspect they can (from watching) bring in a canine and if the canine smells something they then have probable cause (I believe) w/o getting a warrant (this is from memory and not a legal opinion that I have researched).