My thinking: I had previously raised and taken down a few pots with standard cbets; however, given the skill level (or lack thereof) or most players in freerolls, and the size of his raise, I figured he was not playing back with air. If he had a set, why raise on such a dry board, especially when I have been cbetting consistently? Given all of this, I shipped it in. He had AJs, and binked an A on the river.