How dangerous is it to hire a CFI to give you flight lessons? They'll take you up with 0 hours of experience. They'll take you up to do your ATP cert.
If the guy was like "I just found an airplane laying around in my garage and I started flying towards Japan and dropped the bomb the won WWII", that's probably dangerous and fabricated. If you know how to do a preflight inspection before, then you probably watched someone on YouTube do it before, which is basically flight training minus the FAA certification. The big idea is that if you do something wrong, your instructor is there to correct it. If you have that, you aren't being unsafe.