Admissions officers will tell you they are aware of what programs schools have, and take that into account. If your school has no AP with GPA inflation your 3.x is the same as a 4.x at some bigger high school. How true that is idk.
that may be true for colleges looking at local feeder schools ("northwestern knows that my high school doesn't have grade inflation"), but I don't know how that idea scales nationwide or internationally. To steal an example, how does a college in Seattle know that a high school in Illinois has grade inflation or not? is that tracked anywhere centralized?
you could certainly look at past performance of students from that school but that turns into a "legacy system with more steps"...
