Create feature to randomly vary block start times

I would love to see a feature that randomly varies the start time of a scheduled block by 0-[user-set-max] minutes to trap myself into the session without an opposition to edit it or turn on vacation mode. For example, if I set the variable user-set-max to 30 for a block scheduled to begin at 12:30am, the block would actually begin at a randomly determined time between 12 and 12:30.