With the 15th anniversary of the Sept. 11 terrorist attacks coinciding with the first Sunday of the NFL season, the league commemorated the day with pregame ceremonies involving field-size flags and a non-partisan video tribute featuring Presidents George W. Bush and Barack Obama.

Even with players’ politics getting more attention these days than their performances on the field, not even the NFL could have prepared for the way the fans reacted to the presidents’ remarks.

Several social media users who attended NFL games across the country on Sunday reported hearing boos when the video started playing. According to someone who attended Sunday’s Jets game at MetLife Stadium, the scattered boos intensified when Obama appeared on the big screen.

Other fans confirmed — and condemned — the disgust directed Obama’s way, most notably at MetLife, the Baltimore Ravens’ M&T Bank Stadium and the Seattle Seahawks’ CenturyLink Field.

Some commenters expressed frustration with what might appear to be a double standard for how to treat solemn public moments of patriotic reflection. The NFL remains divided over quarterback Colin Kaepernick’s protest during the national anthem before 49ers games, which keeps the door open for more political demonstrations such as Sunday’s boos.