He did not explicitly threaten me. However, because the administration pretty much just listens to what public safety says, things like enrollment were potentially at stake.[0,1] I was not willing to trade those potentials for a search that I knew would result in nothing.
[0] This is evidenced by the fact that my initial refusal was brought up later in a meeting with the administration.
[1] Imagine with me: officer assumes that my refusal implies possession of banned substance, uses refusal to file a report in that vein, two days later I'm force to prove to the administration that I didn't have the banned substance at the time. That's obviously impossible.