The shop called today, and said that while the oil change was done sloppily, the oil is leaking from the area near the timing belt. They wanted me to check when I last had the timing belt changed before they commenced with most of the procedure to change the timing belt. They didn't seem to think it had anything to do with the oil change, even when pushed about it.

It seems like amazing timing to me to happen after driving two miles on the oil change, but coincidences do happen.