If it is a piecing mistake--a block turned the wrong way or something similar--a fresh pair of eyes will often catch what another pair of eyes has stared at for months. Yes I would definitely want to know and Iwould want to be the one to fix the problem. I would never ask my LA'er to do that.
If it is a case of a humped middle or borders so wavy that it is going to affect the total outcome--yes again I would want to know so that I can make the decision whether to still spend all that money for a sub-par outcome.
As for the LA'er just going ahead and fixing the problem and then telling me or not saying anything at all--absolutely not!!That would be insulting me!!