Disagree here @chen.amy. Those controlled lab tests can spot problems you'd never catch in the real world until it's too late. What if the real world just gets lucky?

Absolutely say NO, full stop. Found an active robin's nest tucked behind a client's siding last month and refused service until the fledglings were gone. Some things are just more IMPORTANT than a job or a fence. You NEVER mess with a nesting site.