I believe you could have filled up a gallon or two to be safe and prevent the fuel pump from dieing and not reset trip1 it would still count as long as the gallons total in trip 1 counter shows below the tank spec'ed size of 13.4 gal.
I'm a purest, I'm trying for 600mi on what my car will let me put in and use.
How has your actual gallons pumped compared to the displayed gallons used on the trip? If it is pretty accurate for you then you should have a little more assurance that there's fuel left in the tank, right? Is your car able to be filled completely, as opposed to those who can only fit in 10-11 or so? I've put in just over 13 gallons 2-3 times so my tank is fine, though it does take several clicks to get it filled that much.
If I let it go to click and use the same pump each time, the pump and gallons used per trip match up pretty good typically.
I'm running some experiments as to what happens if I go beyond the click to see how much of the extra fuel I'm able to use. My hunch is not much. I suspect that all I'm doing is pumping it into the vapor recovery of the pump. Last time I filled up I was at 6mi DTE and put in 11.5 gal, which was a few 1/10ths beyond the first click. Of that I had used 11.22 gal for this trip when I refilled at -2mi DTE and pump clicked at around 11.2-11.3 gal (can't remember exactly). That means by both the trip count and the pump count, there was at least 0.2 gal that just vanished.