I was also just thinking about that fake name he used when arrested in Texas, George Carr. Several people here have said that his grandmother's name is Carr. But maybe there is more to it than that. Maybe the name is linked in his mind in some way to a place he had been recently. Sleuthing this shows that the Ivy Creek Natural Area is associated with an African-American family named Carr. Also the name of George Carr is associated with a farm on the northern bank of Ivy Creek where Hessian soldiers were stationed, which has been known ever since as "The Barracks" that is
just to the west of where he lived.
http://babel.hathitrust.org/cgi/pt?q1=%22George%20Carr%22;id=uva.x002672921;view=plaintext;seq=45;start=1;sz=10;page=search;num=31
So not so much trying to get back at "George Carr" but merely being aware of the name in association to where he took Hannah, and blurting it out when he suddenly has to come up with a fake name.