He was pretty dumb, so wouldn't put it past him
Ross Ulbricht is a clever dude, by any rational standard. I conclude that you are not rational. Sorry, but Aristotelian logic alone compels me.
You'd figure he have it setup so if he doesn't input a certain code every 24 hours, the BTC automatically transfers to another BTC address. Every single movie villain has a bomb that blows up without code or connected to heart beat monitor. Didn't wikileaks owner have the same kind of fail-safe plan.