Is it possible to view the users site and content as admin? Because I was helping someone and I was logged in to the network admin account but when we went to his site url, his dashboard came up and we were able to create new posts and so on.
In light of all the privacy violations going on I'd hope I couldn't get into a users account. Or at least have an option to turn that behavior off.
Yes. Yes they can. In my testing and throughout the code you see
switch_to_blog(another_blog);
do_something();
restore_current_blog();
If you weren't able to do that I think WP would not run.
switch_to_blog() doesn't make you an admin in the other site.
switch_to_blog() has nothing to do with users and permissions, it´s used for setting the "focus" of your queries to a different blog in a multisite installation.