“NO SCAN, NO PAY.”

That’s what workers for a Shell contractor were told ahead of speech by President Donald Trump on Tuesday at Shell’s petrochemical plant in Beaver County, Pennsylvania, the Pittsburgh Post-Gazette reported Friday.

Translation: Either attend (and “scan” your ID card to mark your attendance), or take the day off.

CNN reported that workers were given the option of taking paid time off for the day, but that still had the effect of diminishing overtime pay at the end of the week for those who skipped the speech.

“It was understood some would choose not to attend the presidential visit and were given the option to take paid time off (PTO) instead,” Shell spokesperson Curtis Smith told CNN. “As with any workweek, if someone chooses to take PTO, they are not eligible to receive maximum overtime.”

A memo to workers, shared with the network by an unnamed congressional source, read: “Those who are NOT in attendance will not receive overtime pay on Friday.”

Workers who did attend, another Shell spokesperson told the Post-Gazette, would count the hours toward their work week, and toward the time-and-a-half overtime pay that kicks in after a threshold.

Therefore, the Post-Gazette noted, workers who attended Trump’s speech received an overtime rate Friday, while those who didn’t were paid their standard hourly wage.

The spokesperson, Ray Fisher, told the Post-Gazette: “This was treated as a paid training day with a guest speaker who happened to be the president.”

Trump’s visit was an official White House event, not a campaign event, but that didn’t stop the President from imploring the union workers in attendance to pressure union leadership into supporting him.

“And if they don’t [support Trump], vote them the hell out of office because they’re not doing their job,” he said.

One Shell contractor, in talking points sent to workers and obtained by the Post-Gazette, warned: “No yelling, shouting, protesting or anything viewed as resistance will be tolerated at the event.”