@Janna74 That's absolutely super weird and a definite no-no. What a violation of privacy!
She has no business stopping by unannounced, and no business doing her laundry while you're staying.
Perhaps message her politely to find out what she was thinking? There may be some weird explanation that might help you see it in a different light. Or at least give her a chance to acknowledge her blunder and apologize. If it's not explained or resolved to your satisfaction, definitely mention it in a review.
I'm an on-site host, and I feel weird going into the yard just to water the plants- when my guests are gone!! I'm very focused on guest privacy. I don't want anyone to feel uncomfortable. The washer/dryer are in the guest's house, and I just wear dirty clothes if necessary until guests are gone and I can do laundry.
I can't imagine doing such a thing as a host.