I think if you're in your seats doing that, it's fine, but since you were just standing around and spitting them out in a public area, that was the issue. It was wrong of the guy to threaten to bring in the cops after you established that you were a season ticket holder, as it is always best to cater to season ticket owners. At the same time, you aren't entitled to openly make a small mess in an area that isn't your seats. In the end, if you do it again, I'd just have the cup and that way there is no controversy.