Of course you can disregard any warnings and you'll probably survive. I don't have anything to say about dichromate because I'm not a chemist; as far as I'm concerned you're welcome to drink it
As to people hacking on stuff - I've seen so much horrifically dangerous DIY wiring that I stand by my warning whether you believe it or not. A good percentage might survive but there are a hell of a lot that didn't, including people who were not involved in the DIY efforts.
I say this as someone who reckons people should do more experimentation and DIY stuff, and especially they should hack on things they own. However, mains power is fickle stuff that can get to places that you really did not expect it to unless you know exactly what's going on. I'm not saying you should never ever work with the stuff, just that some electrical & electronic education is in order first, i.e. an understanding of basic circuits and exactly how grounding works as a safety feature, as a minimum. You also need to think of the mechanical failure modes (what happens when dropped, bumped, snagged on something; whether any parts like cords are subject to wear) of what you're building, how that might create electrical hazards and how to mitigate those in the construction. Please at least make sure you have proper strain-relief on the supply cord and that all internal cords are covered by a rigid case and therefore not subject to snagging.