Google is your friend. Much of what I mention is personal experience ( I am a farmer with an abandoned railroad cutting through my farm and a cyclist who has ridden sections of the Katy). But dig a little into articles on the Katy and the Rock Island line and you can find plenty of accounts. My quick google found accounts of crimes on other trails.

I could dredge up all up all sorts of news accounts if you have a legitimate interest, but I suspect your question is rhetorical. Further, I’m not opposed to trails. But I also value and respect property rights, security, and privacy. When those issues are taken into account, trails can be an asset to an area.