Why did he refuse to wear the sticker? Well, he was ok with displaying the number of accident-free days on days 1 through 665. But then came day 666... According to the CBS article, the man feared that wearing "the mark of the beast" would "doom him to eternal damnation."
Let's be honest... sounds stupid. But sincerely held religious beliefs should lead to reasonable accommodation (and the interactive process and all that good stuff), even if it sounds silly. So, in theory, it's at least a plausible lawsuit.
For more on this case, check out Jon Hyman's Sympathy for the Devil (as religious discrimination) and Suzanne Lucas's (aka The Evil HR Lady's) 666 Firing: When Demanding Compliance Costs You a Fortune.
Posted by Philip Miles, an attorney with McQuaide Blasko in State College, Pennsylvania in the firm's civil litigation and labor and employment law practice groups.