How the possibility of a battlecruiser dilutes raider patrols

How does the possible presence of a battlecruiser change the hunt for ordinary commerce raiders?

Hunters must group for the worst plausible encounter, which reduces the number of patrols and wears the available ships more quickly.

British Town-class cruisers and battlecruisers illustrate the indirect burden created by a powerful raider. A hunting force might usually encounter only the lighter ship. It must nevertheless be strong enough for the less likely encounter with a fast capital ship, so cruisers have to operate in larger groups. That concentration leaves fewer patrol groups at sea and shortens the maintenance and rest available to the ships that remain active.