Kai, when you say 'deadly' - do you mean something that would cause personal injury or death? Or something that would be detrimental to the operation of the device? English can be such an imprecise language.

I suggested the switcher to eliminate one path of entry to the interference and to eliminate brownout issues.

As for the Lt1785 devices, they seem to work fine for me also but compare the enable and propogation delays and they are significantly larger than for say a MAX485 or 75176 style device. As usual, it pays to look at the specs closely even when the part looks like a drop in replacement!