Well, maybe at your level, everyone had their own bat. In highschool and/or Little League, not everyone has their own bat. I let my team mates use my bat. It doesn't really bother me. And there is a kid on my team that thinks that someone will put a dent on his bad hitting soft-toss..
Depends on what kind of person you are, I guess. I'm not saying that people who don't share their bat are bad people, by the way.