Just want to share a personal experience on the auto return to home function and on the importance of practice and understanding the Mavics commands and most importantly, not to panic in any situation.
So.. I was out flying the Mavic, had a home point set. I was flying low taking some video around my house and I knew the battery was getting low. Just as I was flying under some tree branches the Mavic announces that due to battery level it is going to return to home. The Mavic begins to rise,however being under some large branches this will result in disaster. I immediately pull the left stick down. Two things happen, first the mavic begins to spin about its axis... fine with me as long as it doesn't rise anymore. Second the controller displays the question "Cancel Return to Home" and you either hit "Cancel" or "OK".  Here's where it gets amusing.  I think to myself, "Yes, cancel return to home." So I hit "Cancel".  Obviously the craft remains spinning and I am still holding left stick down.  I'm thinking..."Oh no, Mavic is not responding...what do I do? I run through the command that I just did and relized that I told the craft to Cancel the option to cancel return to home- thus telling the Mavic yes retrun to home.  Thankfully as I still had left stick down the controller again brought up the option to "Cancel Return to Home" this time I hit "OK" and sure enough because I had left stick down the craft then began to come down and land right at my feet.
After this episode I wondered how many people have made a similar mistake, crashed the craft and then assumed that it did not do as was instructed. When infact it was their improper input that was at fault.
Now as to why the Mavic spun about its axis while I was left stick down and trying to decide whether to hit Cancel or OK. That I'm not sure about, but at least it stayed in place until I figured out my error.
So, don't panic, read and understand your manual, practice on the simulator and in safe open areas and you'll be on your way to great experiences with the Mavic.

makes perfect sense and can see where in the moment you could misinterpret the option to cancel the RTH.

Won't hitting the pause button cancel any RTH?

Pressing pause during RTH will pause it under normal circumstances, but i'm also wondering if its different during the failsafe low bat RTH.