Well, that depends on whether people's decisions to drink Comed-Tea are controlled by the Tea's knowledge (??) of when they're going to see something ridiculous and whether it can affect anything else. It also depends on how powerful the mind-control is.

If it just sends a "drink Comed-Tea" impulse whenever something funny's going to happen, the precommitment would probably beat it. If it controls your mind, either you'd only be able to decide that if you were fated for twelve consecutive days of surprises with breakfast, or you'd just forget about it when you weren't fated for a surprise. If it can control the rest of the universe to any extent at all, it'd probably try to make you decide to begin at a time when you were likely to face a lot of surprises, and then conspire to delay breakfasts or make you forget to drink it until something surprising was going to happen. And we can't rule out that, as a desperate measure, it could alter your sense of humor a little, or prompt you to, e.g., turn on the television at the right moment.