I like to live dangerously!!! I wouldn't use this configuration on a Vox AC30 (or any other tube amp) but it has proven simple and effective for my laptops for the last fifteen years and the danger factor is about the same as dying from being hit by a falling roofing tile inside your home!
Seriously though, if this was going to kill me, it would've happened on one of the many band tours I went on in the 90's. The crazy stuff we did on those tours would make people shudder!! ---Creating three phase outlets from three different GPO's (on different phases) wired to a makeshift distro box with a three phase socket on it and a bunch of extension cords was always fun!!!