I don't trim up blocks. You end up cutting off points, so what is the point? I would rather fudge a little. If my blocks are off more than 1/4 inch, I redo them or make another. There are a FEW techniques where trimming down is perfectly fine - say the background for applique which was made larger in the first place.
I also don't square up blocks for swaps. I prefer to leave it to the swapper to decide if they want to fudge or trim. If you cut off the point, the block may be unusable by that swapper.