The people behind me have done it a few times. How can i tell they had "guests" over?

I find beer bottles, coke cans and garbage on MY property. There is the obvious noise from the late night "pool parties" as well.

Normally people dont care what their neighbours do, but when it starts to impact others, people start to care.

Neighborhoods have a lot of societal norms, my house has frequently been referred to as "the rental" even though I've lived here for years and the prior tenants also all had long runs here... even being a rental house in the neighborhood is considered strange here.