I like @shanaqui’s explanation for why it is currently that you can technically cross the bright red line.
As @philip alludes to, there’s theoretically a way to redesign things so that the moment you touch the bright red line, you derail. But it’s way easier said than done and would involve the red line being staircase-shaped. Further musing on that in this old thread:
I actually will be excited to move to that scheme eventually, and I do think it’s cleaner, but it’s a bigger change than, for example, the yellow brick half-plane project. Also I think it will have less impact for normal users who just want to commit to doing certain things every day by a consistent deadline.