That's a good thought, but a half a quart of ATF in 25 gallons of on road diesel is not enough to turn it red like dyed fuel. (You can check that theory an ratio by putting about a 1/2 oz of ATF in a gallon of diesel.) I grew up on a farm an am well aware how dyed fuel seems to never leave the system once you use it and dyed fuel is a fairly deep red in color also.
When I first got my Humvee it had a sticky injector and about a 1/4 tank of fuel in it. I dumped in 5 gallons of fresh fuel and 2 quarts of ATF an ran the **** out of it. Ran it till almost empty an dumped in another 5 gallons of fuel an 1 quart of ATF. By this time she was running smooth so I filled the tank an dumped in another quart of ATF and the second tank fill I started using a half quart of ATF after that. During that time I also changed the fuel filter an fuel lines an there was no hint of red at all.
ATF has been what "the old timers" swear by since I can remember and I have never heard of anybody ever getting even questioned if they had gotten checked. I'm not gonna worry to much.