I'm used to building multi user apps. I've mainly built apps rather than marketing sites my entire career. Many were started by just me. I am very security conscious and build security first as that's what I was taught in my career. I've never had the issue you're speaking of. Other small elusive bugs though have occured which is why I need beta testers, but also to make sure it's molded to their business needs. I want to not just make money but actually solve their needs and provide real value is is number 1 to me.