I don't think this is paranoid at all, so far all the online hosted wallet services, including exchanges, are young companies run by few people with usually que

I don't think this is paranoid at all, so far all the online hosted wallet services, including exchanges, are young companies run by few people with usually questionable technical competence, and hence are very prone to being hacked every now and then. There's no "Google" of Bitcoin yet that you could to some extent trust.