Final answer:
Motorcycle groups should ideally not exceed 5 to 10 riders, and larger groups should split to maintain safety and responsibility.
Step-by-step explanation:
The appropriate size for motorcycle groups before splitting into smaller groups is not provided in the information given. However, the principle regarding group size and behavior suggests that very large groups can lead to challenges in accountability and cohesion. A large motorcycle group exceeding a manageable number might find it more difficult to maintain safety and communication. A common guideline for motorcycle riding is to have groups no larger than 5 to 10 riders. Groups larger than this should consider splitting into smaller, more manageable sub-groups to ensure safety and to minimize the risk of a tragedy of the commons situation, where individual irresponsibility is hidden behind group anonymity. The information about Harley Davidson motorcycles and stolen motorcycles is not directly relevant to the question of optimal motorcycle group size.