I always understood a couple of seconds thinking time were already built into V1 calculations, so any personal tampering with it takes you into territory that may be beyond your knowledge. By that I mean the call 'V1' is made, and you decide immediately Go/No Go. Then a few seconds are allowed for to get the thrust levers back to idle, select reverse and make sure autobrakes and speedbrakes deploy. Simple as that, tamper with it and you are at a lawyers mercy.
On a heavyweight takeoff from BOM, when I called V1, I was 'impressed' how close the end of the runway was. I reported that I did not think we could have stopped even with 4 in reverse. Some months later our Safety team sent me calculations to show that we could have stopped with a couple of hundred yards to spare- which I discounted as wrong. Sure enough, one of our 747s, with a reverser locked out already, lost another engine just below V1, with a brake unit locked out as well. They stopped OK and did not run off the end.
Personal tampering like that is dangerous. You could be obliged to take an unflyable aeroplane into the air. Can you imagine what the Courts would make of you?