I've noticed rick's boots sometimes look like they've been tied by a right handed person. And sometimes like a left.
WHICH IS IT???!!!!!
Even if you're just being facetious...I can come up with a plausible answer (which is all anyone can do):
Some times Andrew Lincoln ties his own shoes, some times they're tied for him as he's sitting in the make up chair.
Has nothing to do with the story, but would explain the knots.