RT::Tickets->LimitWatcher based on RT::Principal->id?

My client created a bunch of RT ids without email addresses. Is there any
way to do a query to find that person’s tickets (ie where they are the
requestor)? RT::Tickets->LimitWatcher is based on email address, and I’d
like to limit based on their RT::Principal->id instead. Is there a call to
do that?

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