Viewing RT as another user?

I’d like to view RT as another user, without having to change or set
their password. How can I do this?

Reason: we’re thinking about turning on self-service via
auto-generated passwords:

but I’d like to see what users will be seeing before I turn this on.

We’ve cheated a little bit by assigning passwords to some unprivileged
users and logging in as them, but there has to be a better way?

We’re just a Bunch Of Regular Guys, a collective group that’s trying
to understand and assimilate technology. We feel that resistance to
new ideas and technology is unwise and ultimately futile.