Lots of discussion here, great! I feel this warrants stepping back and looking at this from a bird’s eye perspective:
The Problem
What you ideally want is something that understands where you have been spending the night and then make you leave that place by some time, getting at least, say, 500m in between you and where you spent the night.
Does Beeminder provide this level of automation currently? Not without some programming, so that’s out the window for now.
What’s the next best thing? The solutions presented here, namely
- Runkeeper requiring you to walk a certain distance before the deadline, or
- IFTTT requiring you to leave a certain area before the deadline.
Both methods have the problem of also respecting anything that happens after the deadline as @hmowilliams pointed out in the video. I am amused at how I managed to miss this problem 
It seems indeed rather obvious in hindsight: There is currently no easy way (aside from Tasker on Android I guess) to chain multiple conditions together in IFTTT, Beeminder, and so on.
Solution
I got good news though! I myself have a goal that would profit from more detailed time restrictions and have already created a small web service that enriches the Beeminder API somewhat. I was thinking of adding this missing functionality for myself in the past but kept not doing it. But now since you’d also profit from this I shall do so right away. I’ll report back once it’s done. Might take a few days, I got some things on my plate right now.
How does this help? Recall when @hmowilliams (in the video) referred to Tasker on Android allowing you to add another constraint (in this case the time). I will basically recreate this as a web service. You can then set up IFTTT to call that web service which will then add the datapoint for you to your Beeminder goal. But only if it is within a certain time of the day. That is the additional time constraint that is missing in this equation.
Sounds complicated? Don’t worry. I think I can create an applet on IFTTT that takes care of most of the work and make that available to everyone and then you can just use that one.
Maybe we can all convince @dreev that this feature would be beneficial for more Beeminder users so I won’t have to implement it myself 
In other news
Definitely not! I always thought I put the pro in procrastination until I read this awesomeness:
Hope this helps!
P.S.: I think c-gold would make for an interesting username, too