Prepare to drop or amend these handbook rules.

The National Labor Relations Board enforces the National Labor Relations Act, a law most employers erroneously believe only affects unionized workplaces and the conduct of union elections. The fact is, the NLRA applies to almost every employer, and the NLRB can exert outsized influence on almost every employer's day-to-day operations.

In fact, NLRB rulings can affect the very rules you write into your handbook. The board's Stericycle decision, issued in August, calls for a wholesale reexamination of the handbook rules that any private-sector employers seek to enforce, even if they do not operate in a union environment.

In Stericycle, the NLRB ruled that for a seemingly neutral handbook rule to be legal, a reasonable employee would have to read it as not banning discussions about working conditions. Otherwise, the rule would "chill" NLRA rights. To defend such a rule, employers must show they have a substantial business interest that requires the rule and that there is no less-restrictive way to meet that goal.

What Stericycle means for you

Check your handbook for any policy that could be read as telling employees they cannot openly discuss poor working conditions. The rules most likely to cause trouble are those calling for civility, defining insubordination and prohibiting critical social-media posts.

Civility. A few days after the Stericycle decision, the NLRB struck down a civility rule that appears in Starbucks' handbook. Starbucks discharged an employee for allegedly using slang for excrement while...