The federal labor board hinted Sept. 30 that it may soon change the legal test for determining when a “wildcat” strike—work stoppages that haven’t been approved by the striking employees’ union—is illegal.

The suggestion came via a footnote in an opinion dismissing allegations that 86 workers at a Coca-Cola bottler in Puerto Rico were unlawfully suspended or fired for participating in a wildcat strike.

Although the National Labor Relations Board’s authority applies only in the private sector, new precedent or rulemaking that curtails union members’ ability to hold a lawful wildcat strike could have significant impact, given the recent and major uptick in labor disputes across the country. The nationwide wave of work stoppages that began in 2018, for example, included a number of wildcat strikes because some happened in states where it’s illegal for public school teachers to strike.

Unauthorized strikes are currently considered legal so long as the workers don’t try to bargain directly with the employer, or take positions that are inconsistent with their union’s stance.

The Republican members of the NLRB have taken to using footnotes to give cues about which existing policies and precedents they will change. Similar hints were dropped ahead of actual decisions to change the board’s positions on union election procedures, and when an employer can move to decertify or oust an existing union.