One can only guess.
Counting yard signs?
Making a note of McCain signs to steal later?
Making a note of McCain signs so the families living in those houses can be purged after the New Era begins?
Looking for stuff to steal after dark? I know when one of my sons lived in Brooklyn some time ago, car thieves would actually be commissioned to steal a certain year and model car, maybe even a certain color, and they’d go around the neighborhood until they found what was wanted.
This was a clean fairly new minivan, 40 to 50 somethings. The driver the husband looked like the college professor type.