Whether accurate or not, a limit has to be decided.

I suspect it's more of an organizational tool problem than simply having a number to limit distribution, and that this is the lowest hanging fruit to create a solution for - for better or worse depending on your use case or needs; and externalized value no longer created by using this limitation may or may not result in a net benefit for you.

Is there also a limit to the number of Circles one can define? That might help with spam prevention.