An attacker could advise your trusting church-mates to download and run an application that turns out to be a virus while they believe it's from you. A real bu

An attacker could advise your trusting church-mates to download and run an application that turns out to be a virus while they believe it's from you. A real but milder story - a customer of mine once complained about the advertising on my website being slightly offensive. I didn't have any advertising. When I investigated, it turned out the advertising was being injected by malware on his own computer. Not that HTTPS would have solved that, but I've heard of ISPs doing similar things where it would be prevented.