Well, if they are in a social services system and trying to back on their feet, having a way to actually get in contact with them is a good thing.... but will this requirement actually be enforced? That's another issue.
I've had to deal with folks in these programs who have no phone or voice mail etc.. and its a pain to get in touch with them, have to call their case worker or their employer if they have one just to get a message to them.