Wild_spot, my post was not in direct response to yours. There were posts suggesting that it if you don't talk to the owners first, you're a bad person for calling, and I disagree. You have an obligation to the horses that you feel need help.
I just think that it's better not to express that kind of concern with strangers. Around here, people can be very defensive about their animals, ESPECIALLY when they know they are at fault. Even if the guy wasn't a sex offender, I would look at the circumstances (i.e. property condition, etc) and decided whether or not it would be safe for me to approach that person.