If you've ever wondered whether allowing an employee to take medical leave will tie your hands if it comes time to challenge that employee's disability claim, take heart. Just because you didn't ask for medical proof of disability once, that doesn't mean you can't later.
Recent case: John Benko worked as a teacher until he voluntarily retired. A few years earlier, his doctor wrote a note recommending Benko take a sabbatical "for medical reasons." The school district allowed it and never asked for specific medical proof. But after he retired, Benko sued for disability discrimination, alleging the school district denied medical coverage in retirement because he was disabled. He argued that because he took a medical sabbatical, the district couldn't attack his claim that he was disabled now.
The court disagreed, saying the district's earlier acquiescence didn't stop it from challenging his disability now. The district eventually won because Benko had no proof of his disability and he ran a farm single-handedly. (Benko v. Portage Area School District, No. 03-233, WD PA, 2006)