What was the social class of the people (citizens) who were thrown to their deaths from the cities walls in ancient Mayan culture?

I had a conversation with a guy a while ago and we were talking about inequality. He said the poorer classes are more likely to be thrown off by social mobility (not literally), thus the concept of "social cities" and the walls between them. The "walls" between the classes are meant to keep people from rising by keeping them in their place. I tried to search about it but I couldn’t find anything about it. I tried asking my social science teacher but she said she never heard of history of Mayans throwing people off their cities walls. Do you know of anything like this? Is it a common concept?