Common area usage and parties

I am hoping someone can provide some guidance on HOA common area usage. We have a semi-landscaped common area right behind our house; trees and a few benches. People sometimes hang out there for short periods of time, which is cool.
Tonight there is a "party" of about 20 kids and 10 adults, very loudly using the space. They have brought in decorations, tables, balloons, so it was clearly planned. It feels like a bit of an invasion and inappropriate use of the space. Does the HOA permit this type of use of a common space?

 

From my perspective:
The HOA Common Area is there for our residents to enjoy, and is in fact owned by the residents.
We do not have any use restrictions/reservation policies.
We often get requests to "reserve" the grounds around the Nature Center or around Hillside Park.
We do not do that.
We do have some rules and regulations about the use of Common Area amenities such as pools, tennis courts, etc.

 

Did the residents clean up after themselves? Were they respectful of the time their get-together ended?

 

I have this very same question. My house backs to a common area that is not accessible from the bike path, only through private homes. What are the rules regarding usage of that space?

 

To update this thread, they did not clean up the area, or at least not thoroughly. There were a few parties this spring and each time, the following day, we picked up a gallon-sized bag worth of food wrappers and trash.
Just today my husband found ribbons tied up in the trees. We are not sure if they were from a recent party or one from the spring.