That's one of my threads from a while ago....check that out....I wasn't the first to bring that topic up, so that thread's got other links on it to previous ones which are all good.
I sometimes use that approach IH, usually I get a line in my head, make a few chords to it and sing garbage over them occasionally picking out something that speaks to me.
And yeah I see what you're saying about being paranoid, I'm the same way. My material is my own and nobody elses to steal. If had recorded it on an album or played it at a gig a few times I wouldn't object to anyone covering it...that's almost inevitable, but the net is full of those who will copy stuff from others and call it their own.
'There's no such thing as bad weather, there's only the wrong clothes...'