Do the rules of your home instance apply when posting to a different instance?

I'm new to the Fediverse and I'm still trying to understand how this all works. While browsing the All/Federated home page, I saw some posts which seemed to be pornographic. It got me thinking about the rules of Lemmy instances. Lemmy.ca has a "no porn" rule. Hypothetically, if I were to use my Lemmy.ca account to post porn on an instance which allows that type of content, would I be in violation of Lemmy.ca's rules?

I guess the question is related to my confusion about where federated content is stored. If I use my Lemmy.ca account to reply to a Lemmy.ml thread, which server does my comment "live" in? If I were to delete my Lemmy.ca account, would all my comments in Lemmy.ml disappear too?