Rule · Chapter 1
cr:1.15.4
If a counter would be added to an object that has a diametrically opposing counter on it, both diametrically opposing counters remain on the object.
Example: If a -1{p} counter is placed on an object with a +1{p} counter on it, they both remain on the object. The counters do not cancel each other out and they are not removed from the object simply because they are diametrically opposing.