Generator's are not that loud, they usually get placed away from the tent anyway. Definitely do not chance it by running power from the house if you've been told not to...blowing a fuse is one of the worst ways to ruin a wedding. Power is needed for all sorts of things: lighting, PA equipment, band/DJ gear and kitchen gear for outdoor weddings. That's a lot of juice to be pulling from a house. We had a brief-case sized generator for our beach ceremony and it was placed far enough away that no one could hear it. Don't worry about the noise, the pros know what to do with it
If mine was loud I didn't notice it. It was tucked away from where we were.
What differentiates an average host and a great host is anticipating unexpressed needs and wants of their guests. Just because the want/need is not expressed, doesn't mean it wouldn't be appreciated.
Re: Generator