Lead Balloon,
My "you are on your own" was intended to mean ---- there is no one answer, 'tis up to you.
However, I would be doing my best to stop, including making certain that the apparent lack of stopping was not caused by failure of spoilers to auto deploy, failure to properly close thrust levers/throttles (you might be amazed what is on some flight recorders/what I have observed in the sim.) or "relying" on auto-brakes.
Megan,
If you read the definition as a anything other than the the GO speed, if the rejected takeoff has not already been commenced, you ain't reading it right.
As to what is built into the derivation of V1, there have been all sorts of changes over the years, far too many to go into here, all to try and make a real world rejected takeoff more likely to succeed, without unacceptable payload penalties, but that doe NOT, in any way, change what the pilot in command is going to do, has to do, on the day it happens for real.
I would suggest I have quite a good handle on this particular issue, including membership a some "interesting" working groups, going right back to SFAR 422B, which is probably before many of you ( and FAR 25) were born.
As I said in my first post, there are still too many FCOMs/text books/training manuals etc., that vary from misleading to just plain wrong.
Tootle pip!!