Final answer:
Unauthorized streaming likely represents the greatest loss of revenue for broadcasters, as it circumvents both subscription and advertising models that are essential to their business.
Step-by-step explanation:
The aspect of piracy that costs broadcasters the most money is likely unauthorized streaming. This is because it enables large numbers of people to access content without paying the subscription or advertising revenues that broadcasters rely on. While signal theft and content licensing issues do present financial challenges, the simple and widespread availability of unauthorized streaming means it can quickly scale to become a substantial revenue loss. Digital advertising is an important revenue stream as well, but its losses are tied to the viewership garnered through legitimate means. Broadcasters like satellite radio companies, such as SiriusXM, depend on subscription fees to provide an ad-free listening experience, underlining the importance of maintaining a subscriber base against the challenges posed by unauthorized streaming.