I have never objected to ignoring private trees, no trees or small trees. I have objected deleting them, but you now have the option of moving them to the trash file which is great. I wish we were able to create more files, location files, surname files, etc, and hopefully Ancestry will implement this. As one poster said, he went back through his deleted files and found some had added a tree or unlocked their tree. Sometimes people just need a little time to get their tree prepared and DNA attached.
I have also objected to blocking them. Even if you don't have time to contact them, they may find how they match you and contact you. Everyone just needs to learn a little patience.