The condo I live in has a rule that people should not leave anything outside of their apartments. There are two reasons to leave things outside of their apartment:
1. To make the outside more attractive.
2. To make the inside more attractive.
The first reason should be allowed and the second should not. When people leave shoes or bicycles outside, they are taking common space to store their ugly or dirty items. This is not reasonable. When people put flowers or decorative mats this should be allowed. It is hard to write a rule that makes this distinction.