I'm pretty sure Jiun-Hsien Wu of MHDT does speak English. You may want to write him with your concerns and see what he has to say. The MHDT DACs are built around non-conductive plexiglass cases. Depending on which one you get there may be relatively more or less vulnerability to shock hazards than with the average DAC because of their case design: I know the Paradisea has openings cut in the top panel, both for the tube and for the design (the name is laser-cut out from the top panel)--All that makes the circuit boards below vulnerable to the aforementioned juice spills and subsequent nuclear fission. Also, the protruding tube on that DAC will be hot when left on, so if the DAC is in reach of your toddler, that may pose another (burn) hazard. I'm glad to hear there are few reports of electrocutions due to stereo gear. I think you are rightly concerned because of what you might have heard about the more open and vulnerable tube preamp and amplification gear, which are certainly nothing I'd leave within reach of a toddler as there are high-currents (not the fruit variety) involved and the warm glowing lights draw the kids in like the Pied Piper. As has been indicated, the risk is less with a DAC in general, but a tube DAC with an exposed tube and circuit board might be worth a second thought. I've heard from my friend, Grant, that he liked the Paradisea very much and he's a pretty discriminating fellow. They certainly have got some good press on Enjoy the Music, as well as various DIY forums and eBay. Don't take the harassing too seriously - your question, as posed, and on face value does occur somewhat amusing, and there are those of us here who do like to have fun. Nothing personal intended. I understand your concerns. Hope that helps.
Marco