That's exactly the reason why I'm not reporting anything anymore. The legal aspect is just really badly designed for this kind of situation. If I find something opened or unsecured by mistake, I just go somewhere else and don't report anything so this way I don't risk anything. That's sad because it's not helping anyone but I just don't want to handle any legal stuff.
Sure, that's the legal environment we find ourselves in, and in many respects it's short sighted and counter productive, i.e. it actually fosters weak security in critical settings and the chance of those weaknesses being taken advantage of by malicious entities.