I assume they work to optimize their panhandling profits. A/B testing various looks, locations, signs, and other tactics to get the most money out of people walking by.

The first thing I thought was a engineer who is out of work and can't find any.

I assume they work in the United States, so their day job (engineering of some sort) only pays health insurance and stock options. To get cash for day-to-day expenses, they pull a shift pan-handling outside the local bank. So a "panhandling engineer" is an engineer who panhandle, not a person who specializes in engineering panhandling solutions.

SaaS developer