Agreed there is a small 'jolt' to withstand. But normal adults wouldn't even feel it. Believe me, it IS safe.
And then going back to the original. Even though this should be in some other thread, here is something else that came up.
I had Verizon DSL for my computer. In the original setting where I had 'incoming' dial at only one place, I had the rest of the phone lines using the little 'boxed cables' that they sent with the installation kit. After rewiring as above, Internet was going slow. Fortunately they ( Verizon) sent me 4 of those boxed wires which I used for EACH of the phone lines in all the different rooms and then I was fine with my Internet.
Of course, I could 'open' up one of the boxed wires and connect to the 'inside' phone box ( kinda like series connection ) to take care of the 'phone line noise'. Then I would not have to worry about phone lines in the rest of the house affecting the DSL.
Just something to keep in mind.