I can just envision that You announce, they make a fast movement to turn and leave, you think that they’re attacking and you end up shooting them in the back. Good luck defending that one in MA.
There are some experienced and knowledgeable instructors here who can better expand on this, but one reason to at least announce that you see them is if you aren’t sure if the person is a friendly who is supposed to be there or not, or you have some question about hostile intent. Years ago my neighbor’s senile mother went into the unlocked front door of another neighbor at around 9 p.m., so there are real good reasons as to why you don’t come out blasting. In that case I wish the senile mother went in blasting because the c*nt liberal nutter of a wife in the house freaked out and called the police and wanted to press charges, and she knew that woman and her son well. He used to plow her driveway for nothing just to be a nice guy. He stopped doing that after that little incident.