"dozens of immigrants have signed powers of attorney authorizing relatives and friends to pick up their children from school and access their bank accounts to pay their bills in the event they are arrested by immigration agents."

This seems to me more fudged reporting from AP.

 If you are legally here you have nothing to fear.
The reporter is putting something into the situation to make it seem worse than it is.
A real reporter would have written "Illegal immigrants have ....."
If this was to much, the tamer, although less accurate,  "undocumented immigrants have ...., "