It would be nice to be able to use ManicTime to plan my day as well. As it is now, I use a separate tool for planning what I'm going to do, and then transfer over all the tasks into ManicTime to track them. You can currently add tags for future work, but these estimates may end up being incorrect. And when you go back to manic time, there is no way to tell which tags you entered after working on them and which tags were entered before starting them. Allowing users to enter tags for future work, and not differentiating them from tagging past work is likely to result in incorrect time-tracking.

I imagine it could work somewhat similar to the billable attribute, but would be automatically added, and then there would be an option to confirm tentative tags after they happen, which would remove the "tentative" attribute. It could make sense to differentiate between tentative tags after the current time, and ones that were added tentatively but can now be confirmed.

Really, any implementation that facilitates planning future work would be helpful!