I also say no to opting out. My kids are far from PG, but middle kid has twice received perfect scores on both the math and writing portions of the state standardized tests. Most kids consider them easy and boring, but I don't know any kids who opted out. I think it sets a bad precedent and might lead to others opting out, dragging down scores.
As far as the 7th/8th grade test, if accelerated is what it is here, I would say no. 7th and 8th grade means Algebra I and Geometry here, including rigorous proofs. I don't see how any kid would understand the proofs portion if they hadn't been exposed to it. However, if accelerated is just more pre-algebra, I say it couldn't hurt to take the test.
