Personally, I got a no-bumping policy on my own board, because if this was available to the author of the thread, they would simply be bumping their own threads all the time to make sure they stayed on top. Like, I have fanfictions on my board, and the authors could constantly hit the bumper to make sure it got everyone's attention.
Edit: Any way to make it so that when you choose Make Thread Older, you can enter manually how many days you want it to age? Because if you want it to go to the bottom, you'll have to click many times!